Parsun F30/F40 EFI Outboard Motor Service Manual
Table of contents
- Preface
- Overview
- Specification
- Electrical system
- Dimensions
- Fuel system
- Basic maintenance
- Electrical system
- Fuel system
- Engine
- Precautions
- Check the compression pressure
- Check oil pressure
- Special tool
- Remove the engine
- Pulley and timing belt
- Disassembly and inspection
- Valve spring
- Valve rocker and rocker shaft
- Camshaft
- Check the oil pump
- Joint surface of cylinder head and engine body
- Replace valve guide
- Check valve seat ring
- Trim the valve seat ring
- Install the valve
- Assemble cylinder head
- Piston
- Cylinder bore
- Outside diameter of piston pin
- Piston ring
- Inner diameter of connecting rod small end
- Connecting rod large end backlash
- Check connecting rod bolts
- Crankshaft
- Crank pin oil clearance
- Main journal oil clearance
- Reinstallation
- About water
- Bottom cover
- Water unit and bracket
- Manual warping device
- Underwater part
- Common faults and solutions
Overview
Identification Mark
The serial number is printed on a label which is fixed to the port side of the clamp bracket or the upper part of the rotary bracket. The serial number is recorded in the blank of the label to help you order spare parts from dealers or for your reference in case the engine is stolen.

- Position of the serial number
The SN indicates the following:

Selection of propeller
The performance of the outboard motor is seriously affected by the propeller. Improper selection will have adverse effects on the motor. When the ship runs in full load, the motor will operate at low speed for a long time. At this time, the propeller with smaller pitch should be selected, whereas the propeller with larger pitch should be selected to maintain the normal operation of the engine.
When the engine is at maximum load, if the throttle is half or more of the full throttle range, the selected propeller is appropriate.
| Propeller dimensions | Material |
|---|---|
| 3-11 " 8 3 ×12" | Aluminum alloy |
| 3-11 " 8 1 ×13" | Aluminum alloy |
Protection at work
In order to prevent danger or accident during maintenance and improve work quality, please observe the following safety regulations.
- Fire prevention
Gasoline and various lubricating oils and greases are easy to burn; Keep away from heat sources, sparks and open flames during operation.
- Ventilation
Gasoline vapor and engine exhaust gas are highly toxic. Massive inhalation of such substances can cause shock and even death. When testing the engine indoors, please keep good ventilation conditions.
- Self-protection
gloves and safety shoes when necessary.

- Use of lubricants and sealants
Only products provided or recommended by Parsun can be used when maintaining and repairing the outboard motor.
Under normal circumstances, the lubricant mentioned in this Manual will not damage your skin. However, please take protective measures before use to reduce risks.
① Apply protective cream on both hands before overhauling the outboard motor;
② Replace and clean the clothes as soon as possible after they are contaminated by the lubricant;
③ Avoid skin contact;
④ Wash your hands and skin carefully with soap and hot water after contact with the lubricant;
⑤ Wipe the spilled grease with a clean, lint-free rag.
- Develop good work habits
① Tighten nuts, bolts and screws according to the specified torque from large size to small size, from the center to the outside.
② Use recommended special tools to avoid damage to parts. Use the right tools in the proper way.
Disassembly and assembly
When disassembling and assembling the outboard motor, please follow the following principles:
- Please use special tools when disassembling and assembling the parts of the outboard motor;
- Remove dust and dirt before decomposing the parts;
- Apply engine oil on the contact surface of moving parts before assembly;
- When installing the bearing, place the manufacturer's mark in the specified direction and fully lubricate it;
- Before installation, coat a thin layer of waterproof lubricating oil on the protruding part and periphery of the oil seal;
- After assembly, check whether the moving parts work normally.
Disposable parts
Parts such as gasket, oil seal, O-ring, cotter pin and spring ring are disposable parts, and they must be replaced before reinstalling the outboard motor.
Pre-delivery inspection
To ensure the normal use by customers, please carry out the following inspection before delivery.
- Check the fuel system.
Check whether the fuel hose is securely connected and whether the fuel tank is full.
Note:
As it is a four-stroke engine, premixed fuel cannot be used.
- Check the oil level.
① Check engine oil level.
Pull out the oil dipstick and observe the oil level through the dipstick.
- Oil dipstick 2. High mark 3. Low mark


Make sure the oil level is between the high mark and the low mark; Drain oil when the oil level is above the high mark and add oil when the oil level is below the low mark.
- ② Check gear oil level
Unscrew the oil level plug and observe whether the gear oil overflows in the oil level plug.
If yes, install the oil level plug and tighten it according to the specified torque; If not, fill with gear oil.
- Oil level plug

- Check the steering system. Check whether the steering is smooth;
- Check shift and throttle operation.
Check whether the shift operation is smooth; Check whether the throttle grip operates smoothly from the full-close position to the full-open position.
- Check the emergency stop switch assembly. Check whether the engine stops when the emergency stop switch assembly is pressed
and hold or the engine stop safety line is pulled out.
- Check the cooling water peep door. Check the cooling water while the motor is running Check whether the cooling water flows out of the
cooling water observation hole.
- Running-in operation.
- ① 1 st hour: The engine runs at 2000 rpm or about half of the throttle.
- ② 2 nd hour: Run the engine at 3000 rpm or about 3/4 of the throttle.
- ③ The next 8 hours: Avoid running at full throttle for 5 minutes continuously.
- Inspection after running-in operation
- ① Check the gear oil for water.
- ② Check the fuel line for leaks.
- Cooling water observation hole

- ③ After running-in operation, run the engine at idle speed and use the washing tool to flush the cooling water channel with fresh water.
- After running-in operation, check the idle speed of the engine.
- ① Preheat the engine for 5 minutes.
- ② Measure the idle speed using tachometer.
If the specified value is not met, adjust it. Idle speed value: 900~1000rpm.
- ③ After idle adjustment, accelerate the speed several times to check the engine stability. Note:
Idle adjustment needs to be done by qualified maintenance personnel with professional equipment; Adjusting at will may cause startup difficulty, weakness, jitter and other faults of the engine.
Special tools and testing equipment
Various special tools and testing equipment will be used when repairing and maintaining the outboard motor. Using these tools and equipment expertly and correctly can improve your work efficiency and effectively avoid injuries to personnel and the outboard motor.
Special tools:



Clearance gauge Piston slideway Flywheel gripper and flywheel puller



Oil filter spanner Bearing puller Valve spring compressor kit

Underwater unit housing cover bearing installation tool

Underwater unit housing cover assembly installation tool

Underwater unit housing cover oil seal installation tool

Underwater unit housing cover needle bearing installation tool
Underwater unit needle bearing installation tool

Drive shaft bearing jacket installation tool


Drive shaft bearing installation tool

Drive shaft seal oil seal installation kit

Drive shaft spline sleeve Pinion nut spanner

Testing equipment:

Digital tachometer Digital multimeter Peak voltage adapter


Disassembly schematic diagram and symbol description Description of disassembly schematic diagram

Forward gear bearing casing installation kit

- ① Exploded view of parts.
- ② Thread specification and specified torque.
- ③ Points where oil, sealant or locking agent are applied
Parts list.
Symbol description

Specification
Outboard motor parameters
| Category | Item | Data |
|---|---|---|
| Overall dimensions | Overall length (B/F) | 1173/768mm |
| Overall dimensions | Overall width (B/F) | 426/410mm |
| Overall dimensions | Overall height (L) | 1361mm |
| Overall dimensions | Overall height (S) | 1234mm |
| Overall dimensions | Stem board height (L) | 508mm |
| Overall dimensions | Stem board height (S) | 381mm |
| Weight | BWL-D | 101.5 kg |
| Weight | BWS-D | 99.9 kg |
| Weight | FWL-T | 100.6 kg |
| Weight | FWS-T | 99 kg |
| Performance | Maximum output F30 | 22 kW @ 5500 r/min |
| Performance | Maximum output F40 | 29.4 kW @ 5500 r/min |
| Performance | Full throttle operating range | 5000-6000 r/min |
| Performance | Maximum fuel consumption F30 | 10.5 L/h @ 6000 r/min |
| Performance | Maximum fuel consumption F40 | 13.8 L/h @ 6000 r/min |
| Performance | Idle (neutral position) | 950 +/- 50 r/min |
| Engine | Engine type | In-line four-stroke, overhead cam |
| Engine | Number of cylinder | 3 |
| Engine | Displacement | 747 cm3 |
| Engine | Cylinder bore x stroke | 65 mm x 75 mm |
| Engine | Compression ratio | 9.4 |
| Engine | Oil supply mode | Electronic fuel injection |
| Engine | Control mode (B) | Steering handle |
| Engine | Control mode (F) | Remote control |
| Engine | Start-up mode | Electric start |
| Engine | Ignition system | ECU |
| Engine | Spark plug | DPR7EA-9 (NGK) |
| Engine | Firing order | 1-2-3 |
| Engine | Maximum generator output | 12 V, 17 A |
| Engine | Cooling system | Water cooling |
| Engine | Exhaust system | Through the propeller hub |
| Engine | Lubrication system | Wet lubrication |
| Engine | Fuel type | Regular unleaded petrol |
| Engine | Fuel grade | RON 91 |
| Engine | Type of engine oil | Four-stroke engine oil |
| Engine | Engine oil grade (API) | SE, SF, SG, SH, SJ |
| Engine | Engine oil grade (SAE) | 10W30, 10W40 |
| Engine | Engine oil level | 1.9 L (change oil filter) / 1.7 L (without) |
| Engine | Type of gear oil | Hypoid gear oil |
| Engine | Gear oil grade (API) | GL-4 |
| Engine | Gear oil grade (SAE) | 90 |
| Engine | Gear oil level | 0.43 L |
| Bracket/Driving | Inclined angle | 64 degrees |
| Bracket/Driving | Steering angle | 45 degrees + 45 degrees |
| Bracket/Driving | Trim angle | -3 to 16 degrees (stem board at 12 degrees) |
| Bracket/Driving | Gear | F-N-R |
| Bracket/Driving | Transmission ratio | 2.0 (26/13) |
| Bracket/Driving | Gear type | Spiral bevel gear |
| Bracket/Driving | Clutch type | Claw clutch |
| Bracket/Driving | Propeller shaft type | Spline |
| Bracket/Driving | Propeller direction | Clockwise (rear view) |
Maintenance information
Engine
| Component | Item | Data |
|---|---|---|
| Power unit | Minimum compression pressure | 840 kPa |
| Power unit | Lubricating oil pressure (idle speed) | 230 kPa |
| Cylinder cover | Buckling limit | 0.1 mm |
| Cylinder cover | Inner diameter of camshaft hole | 37.00-37.025 mm |
| Cylinder block | Cylinder bore | 65.00-65.013 mm |
| Cylinder block | Wear limit | 65.1 mm |
| Cylinder block | Taper limit | 0.08 mm |
| Cylinder block | Roundness limit | 0.05 mm |
| Piston | Diameter of piston | 64.930-64.945 mm |
| Piston | Height of measuring point | 3 mm (from bottom of piston) |
| Piston | Piston to cylinder clearance | 0.055-0.085 mm |
| Piston | Piston pin bore aperture | 16.002-15.985 mm |
| Piston pin | Outside diameter | 15.965-16.008 mm |
| Piston ring (top) | Thickness | 1.17-1.19 mm |
| Piston ring (top) | End face width | 2.25-2.4 mm |
| Piston ring (top) | End gap | 0.15-0.30 mm |
| Piston ring (top) | Lateral clearance | 0.02-0.06 mm |
| Piston ring (second) | Thickness | 1.47-1.49 mm |
| Piston ring (second) | End face width | 2.60-2.80 mm |
| Piston ring (second) | End gap | 0.30-0.50 mm |
| Piston ring (second) | Lateral clearance | 0.02-0.06 mm |
| Piston ring (oil) | Thickness | 2.36-2.48 mm |
| Piston ring (oil) | End face width | 2.75 mm |
| Piston ring (oil) | End gap | 0.20-0.70 mm |
| Piston ring (oil) | Lateral clearance | 0.04-0.18 mm |
| Camshaft | Intake cam height | 30.83-31.09 mm |
| Camshaft | Exhaust cam height | 30.83-31.09 mm |
| Camshaft | Diameter of base circle | 25.90-26.10 mm |
| Camshaft | Journal diameter | 36.935-36.955 mm |
| Camshaft | Roundness limit | 0.03 mm |
| Camshaft | Journal oil clearance | 0.045-0.085 mm |
| Valve clearance (cold) | Intake valve | 0.15-0.25 mm |
| Valve clearance (cold) | Exhaust valve | 0.25-0.35 mm |
| Valve cone width | Intake valve | 1.84-2.97 mm |
| Valve cone width | Exhaust valve | 1.98-3.11 mm |
| Valve | Contact width with seat ring | 0.9-1.1 mm |
| Valve edge thickness | Intake valve | 0.8 mm |
| Valve edge thickness | Exhaust valve | 0.9 mm |
| Valve head diameter | Intake valve | 31.9-32.1 mm |
| Valve head diameter | Exhaust valve | 25.9-26.1 mm |
| Valve stem diameter | Intake valve | 5.475-5.490 mm |
| Valve stem diameter | Exhaust valve | 5.460-5.475 mm |
| Valve guide | Inner diameter | 5.500-5.518 mm |
| Valve guide | Clearance between guide and stem | 0.025-0.058 mm |
| Valve | Stem roundness limit | 0.03 mm |
| Valve spring | Free length | 40.0 mm |
| Valve spring | Minimum free length | 38.4 mm |
| Valve spring | Tilt limit | 1.7 mm |
| Connecting rod | Inner diameter of small end | 15.985-15.998 mm |
| Connecting rod | Inner diameter of large end | 36.000-36.016 mm |
| Connecting rod | Oil clearance of large end | 0.020-0.052 mm |
| Connecting rod bearing thickness | A (Black) | 1.496-1.490 mm |
| Connecting rod bearing thickness | B (Brown) | 1.490-1.484 mm |
| Crankshaft | Main journal diameter | 42.984-43.000 mm |
| Crankshaft | Crank pin diameter | 32.984-33.000 mm |
| Crankshaft | Crank pin width | 21.00-21.07 mm |
| Crankshaft | Large end backlash | 0.05-0.22 mm |
| Crankshaft | Main journal roundness limit | 0.05 mm |
| Thermostat | Open temperature | 58-62 C |
| Thermostat | Full open temperature | 70 C |
| Thermostat | Minimum opening height | 3 mm |
| Crankshaft main journal | Inner diameter | 46.000-46.016 mm |
| Crankshaft main journal | Oil clearance | 0.012-0.044 mm |
| Crankshaft spindle bearing bush | A (Black) | 1.500-1.494 mm |
| Crankshaft spindle bearing bush | B (Brown) | 1.494-1.488 mm |
Measurement conditions: The ambient temperature is 20 C.
Underwater unit
| Item | Item | Data | Item | Data |
|---|---|---|---|---|
| Backlash | Pinion to forward gear | 0.18~0.66mm | Optional gear shim | 0.10, 0.12, 0.15, 0.18, 0.30, 0.40, 0.50mm |
| Backlash | Pinion to reverse gear | 0.75~1.23mm | Optional gear shim |
Electrical system
Ignition and ignition control system
| Item | Item | Data | Item | Item | Data |
|---|---|---|---|---|---|
| Ignition timing | At idle speed | TDC 2º ±0.5° | Peak output voltage of ignition coil | Secondary output voltage | ≥34KV |
| 5000 r/min | BTDC 25° ±0.5º | Peak output voltage of ignition coil | Primary resistance | 1.2±0.12Ω | |
| Spark plug clearance | Spark plug clearance | 0.8~0.9mm | Peak output voltage of ignition coil | Secondary resistance | 12±1.2KΩ |
| Peak output voltage of magneto | 1500 r/min (no-load) | 47.2V | Output peak voltage converter of rectifier regulator | 1500 r/min (no-load) | 41.9V |
| 3500 r/min (no-load) | 106V | Output peak voltage converter of rectifier regulator | 3500 r/min (no-load) | 99.8V | |
| Magneto resistance (green-green) | Magneto resistance (green-green) | 0.59±0.1Ω |
Measurement conditions:
Unless otherwise specified, the ambient temperature is 20℃ during measurement.
Charging system
| Item | Data |
|---|---|
| Output peak voltage at start (no-load) | 14.0 V |
| Output peak voltage at 1500 r/min (no-load) | 45.0 V |
| Output peak voltage at 3500 r/min (no-load) | 102.0 V |
| Magneto resistance | 0.561-0.759 Ohm |
| Fuse | 30 A |
| Rectifier regulator output at 1500 r/min (no-load) | 13.0 V |
| Rectifier regulator output at 3500 r/min (no-load) | 13.0 V |
Seating torque
Specified torque
| Mounting position | Mounting position | Mounting position | Name | Thread specification | Torque |
|---|---|---|---|---|---|
| Spark plug | Spark plug | - | - | 18 Nm | |
| Flywheel | Flywheel | Nut | M20 | 157 Nm | |
| Cylinder cover | First tightening | Bolt | M9 | 23 Nm | |
| Cylinder cover | Second tightening | Bolt | M9 | 47 Nm | |
| Cylinder cover | First tightening | Bolt | M6 | 6 Nm 12 Nm | |
| Second tightening Oil filter | Second tightening Oil filter | - | - | 18 Nm | |
| Oil filter stud | Oil filter stud | - | - | 40 Nm | |
| Lock nut (rocker arm) | Lock nut (rocker arm) | Nut | M6x0.75 | 13.5Nm | |
| Engine assembly | Engine assembly | Bolt | M8 | 21 Nm | |
| 6 Nm | |||||
| Exhaust cover plate | First tightening | Bolt | M6 | 12 Nm | |
| Thermostat | Second tightening cover | Bolt | M6 | ||
| Bolt | M6 | 7Nm | |||
| Crankcase | First tightening | Bolt | M8 | 15 Nm | |
| Second tightening | Bolt | M8 | 30 Nm | ||
| First tightening | Bolt | M6 | 6 Nm | ||
| Second tightening | Bolt | M6 | 12 Nm |
| Mounting position | Mounting position | Mounting position | Name | Thread specification | Torque |
|---|---|---|---|---|---|
| Engine | Connecting rod | First tightening | Bolt | M6 | 6 Nm |
| Engine | Connecting rod | Second tightening | Bolt | M6 | 17 Nm |
| Engine | Driven pulley | Driven pulley | Bolt | M10 | 38 Nm |
| unit assembly | Bolt | M10 | 40 Nm | ||
| Underwater Underwater | Underwater Underwater | Bolt | M8 | 40 Nm | |
| Water intake | Water intake | Screw | M5 | 1 Nm | |
| Oil drain bolt | Oil drain bolt | Bolt | - | 9 Nm | |
| Oil inspection hole | Oil inspection hole | Bolt | - | 9 Nm |
| Pinion | Nut | M22 | 74 Nm | |
|---|---|---|---|---|
| Propeller nut | Nut | M14 | 35 Nm | |
| Above water | Steering handle | Nut | M10 | 10 Nm |
| Steering handle | Self-locking nut | M10 | 22 Nm | |
| Exhaust manifold | Bolt | M6 | 10 Nm | |
| Throttle grip | Screw | M5 | 2 Nm | |
| Shift linkage bracket | Bolt | M6 | 10 Nm | |
| Gear spring plate | Bolt | M6 | 10 Nm | |
| Small cover plate of bottom cover | Bolt | M6 | 10 Nm | |
| Clamp bracket | Self-locking nut | - | 45 Nm | |
| Oil drain bolt | Bolt | M14 | 27 Nm |
Average torque

Dimensions
Overall dimensions
| Nut a | Bolt b | Torque |
|---|---|---|
| 8mm | M5 | 5Nm |
| 10mm | M6 | 8 Nm |
| 12mm | M8 | 18 Nm |
| 14mm | M10 | 36 Nm |
| 17mm | M12 | 43 Nm |
BWL-D:

BWS-D:

FWL-T:

FWS-T:


Maintenance Interval Chart
| Initial maintenance | Initial maintenance | General maintenance interval | General maintenance interval | ||
|---|---|---|---|---|---|
| Project | Content | 10 hours (1 month) | 50 hours (3 months) | 100 hours (6 months) | 200 hours (1 year) |
| Anode | Check/replace | ○ | ○ | ||
| Anode (internal) | Check/replace | ○ | |||
| Cooling water channel | Clean | ○ | ○ | ||
| Spark plug | Clean/adjust/replace | ○ | ○ | ||
| Grease filling point | Add grease | ○ | |||
| Fuel filter | Check/replace | ○ | ○ | ○ | |
| Fuel system | Check | ○ | ○ | ○ | |
| Fuel tank | Check/clean | ○ | |||
| Idle speed | Check/adjust | ○ | ○ | ||
| Engine oil | Replace | ○ | ○ | ||
| Oil filter | Replace | ○ | |||
| Valve clearance (OHC) | Check/adjust | ○ | ○ | ||
| Ignition timing | Check | ○ | ○ | ||
| Thermostat | Check | ○ | |||
| Gear oil | Replace | ○ | ○ | ||
| Water pump | Check | ○ | |||
| Propeller and cotter pin | Check/replace | ○ | ○ | ||
| Timing belt | Check/replace | ○ | ○ | ||
| Throttle cable | Check/adjust | ○ | |||
| Shift lever/shift cable | Check/adjust | ○ |
Note:
Flush the outboard motor with fresh water immediately after running in salt water, sewage or muddy water.
If leaded gasoline is used frequently, check the valve and related parts every 100 hours.
Warning:
The timing belt needs to be replaced every 1000 hours (5 years); Avoid engine damage or injury accident caused by sudden fracture of timing belt due to aging.
Fuel system
- Check the fuel tank, fuel pump and fuel pipe.
Check the fuel tank, fuel pump and fuel pipe for leakage or damage, and replace them if necessary.
Check the fuel filter core on the fuel tank for dirt, and clean or replace it if necessary.


Basic maintenance
- Check the fuel connector.
Check the fuel connector for cracks, leakage or damage. Replace it if necessary.
- Check the fuel filter.
Check whether the fuel filter is cracked or damaged, and check whether there is dirt in the fuel filter.
If yes, replace the fuel filter.

Note:
Wipe off the spilled fuel.
Engine
Engine oil level
- Remove the oil dipstick and check whether the oil level is between the upper and lower marks of the oil dipstick;
- If the oil level is above the high mark, discharge the engine oil; If the oil level is below the low mark, add engine oil.

- Oil dipstick 2. High mark 3. Low mark

Note:
Run and then turn off the engine, and let it stand for several minutes; Check the oil level with the oil dipstick again.
If the oil level is not within the specified range, add/discharge the oil to the specified value.
Change engine oil
- Remove the oil cap, oil drain bolt and bolt gasket; Discharge the oil.
- Install new bolt gasket and install oil drain bolt.
- Add engine oil through the oil port.


Engine oil level: 1.7 L (oil filter not changed)
1.9 L (oil filter changed)
Oil type: API: SE, SF, SG, SH, SJ or SAE: 10W30, 10W40
- Install oil cap.
- Check the oil level.
Valve clearance
- Unplug the engine stop safety line from the emergency stop switch assembly and remove the spark plug cap from the spark plug.
- Remove the fuel pump and cylinder head cover.
- Check the timing belt for slack, aging, or damage. Replace it if necessary.
- Turn the flywheel clockwise. Align the mark '1" on the driven pulley with the mark "▼" on the cylinder head.
Check the clearance between intake and exhaust valve of Cylinder 1. Correct it if necessary.
- Turn the flywheel 120° clockwise. Align the mark " △ " on the driven pulley with the mark "▼" on the cylinder head.
Check the clearance between intake and exhaust valve of Cylinder 2. Correct it if necessary.
- Turn the flywheel 120° clockwise. Align the mark " △ " on the driven pulley with the mark "▼" on the cylinder head.
Check the clearance between intake and exhaust valve of Cylinder 3. Correct it if necessary.
Note:
It is strictly forbidden to turn the flywheel counterclockwise so as to avoid damage to the valve system.
Note:
Two places are marked with " △ ", which are symmetrically arranged on both sides of the mark "1" and have an 120° included angle with the mark "1".
Adjust the valve clearance when the engine is cold.
| Valve clearance (Cold-state) | Intake valve Exhaust valve | 0.15 |
|---|
- Loosen the lock nut and rotate the adjusting screw until the specified valve clearance is reached.
Note:
Turn clockwise the adjusting screw to reduce valve clearance.
Turn counterclockwise the adjusting screw to increase valve clearance.
- Reinstall the removed parts.
Spark plug
- Remove the spark plug cap and then remove the spark plug.
- Remove carbon deposits from the spark plug electrodes.
- Check whether the electrodes are corroded, whether there are deposits and whether the gaskets are damaged. If necessary, change the spark plug.
- Check whether the electrode gap meets the specified value; If necessary, replace the spark plug.
- Install the spark plug and tighten it with the spark plug wrench according to the specified torque.
Specified torque: 18 Nm
Control system
Throttle push-pull cable
- Put the throttle grip in the closed position; Please put the shift lever to the neutral position for the front operating model.
- Check whether the throttle actuator driving pulley is in contact with the check plate on the controller cable holder.
If not, adjust the throttle cable.

- Check plate.
- Loosen the throttle cable adjusting nut and adjust the throttle cable position; After adjustment, tighten the throttle cable adjusting nut
The throttle control is realized by connecting the front operating model with the fixed column on the throttle actuator through the push-pull cable 2
- Fixed column; 2. Push-pull cable joint; 3. Lock nut; Step 4. Clip clutch


The adjustment method is as follows:
- Remove the clip clutch, remove the push-pull cable joint, and loosen the lock nut of the push-pull cable joint.
- Adjust the screw-in depth of the joint so that the joint hole is aligned with the fixed column of the throttle actuator driving pulley.
Note:
The push-pull cable joint must be screwed in more than 8 mm.
- Sleeve the adjusted push-pull cable joint into the fixed column, install the clip clutch and tighten the lock nut.
Shift operation
When shifting from neutral to forward or backward, check the smoothness of shift operation. Adjust the columnar nut if necessary.
Underwater unit Gear oil
Check the amount of gear oil:
Remove the oil level plug screw, if there is gear oil overflow, the oil amount is correct; If there is no overflow of oil, add gear oil.

1. Oil level plug screw
Replace gear oil
- Position the outboard motor vertically.
- Place a container with sufficient capacity under the outboard motor.
- Remove the oil drain screw, and then remove the oil level plug screw; Drain gear oil.
- Use the pressure filling device to inject gear oil into the oil drain screw hole.
- When gear oil overflows from the oil level plug hole, install the oil level plug screw.
- Install the oil drain screw; Wipe off the spilled gear oil.
- Oil level plug screw 2. Oil drain screw

Note:
Check the discharged gear oil. If the gear oil is emulsified, check the seal and replace the oil seal if necessary; If the gear oil contains metal debris, check the gears and bearings.
Note:
A new drain plug gasket must be replaced every time.
Air tightness inspection of underwater unit
Connect the leak detection device to the oil level plug hole to detect the air tightness of the underwater unit. If the pressure drops (the pressure is 1kg/cm 3 ), check the oil seal and other components.
General maintenance
Anode
Check the anode of underwater unit; Remove oil stains and scale; If damage or corrosion exceeds 1/2, replace the anode.
Note:
Do not oil or paint the anode to avoid anode failure.
0~25mm
(0-1in)
Lubricating point
- Fill or apply waterproof grease with an oil gun at the position shown.
- Apply anti-corrosion grease to the propeller shaft.

Cooling water channel
- Check whether the inlet of cooling water channel is blocked. Clean it if necessary.


0~25mm
(0-1in)
- Inlet of cooling water channel
- Place the outboard motor in water, ensure that the water level is above the anti-swirl baffle, and start the engine.
- Check whether there is water flowing out of the cooling water observation hole. If there is no water flow or the water flow is interrupted, check the cooling water channel in the outboard motor.
- Cooling water observation hole

Thermostat
- Remove thermostat cover and then remove thermostat.
- Hang the thermostat in a container containing water.
- Heat the container.
- Check the opening of thermostat valve at the specified water temperature; If it does not meet the specifications, replace it.
- Install thermostat and thermostat cover, and tighten the bolts to the specified value.
| Water temperature | Valve opening height |
|---|---|
| Below 60℃ | Do not open |
| Above 70℃ | Greater than 3mm |
Propeller
Check propeller blades and internal splines for rupture, damage or wear. Replace them if necessary.
Electrical system
Precautions
When monitoring and repairing the ignition system, be careful not to put your hands, clothes, hair or accessories close to the running flywheel.
Check the ignition coil on the insulated workbench to prevent electric leakage and electric shock.
When the engine is running, do not touch the ignition coil or spark plug so as to avoid electric shock. Make sure that the wires are kept away from the running flywheel to avoid cutting off the wires or wearing the insulation of the wires.
When replacing fasteners (nuts, bolts), please use the parts provided by the manufacturer or of the same material and strength, and tighten according to the specified torque.
Disassembly schematic diagram

| REMARKS |
|---|





Spark plug ignition
- Remove the spark plug cap from the spark plug.
- Connect the ignition detector to the spark plug cap.
- Start the engine and observe the spark through the discharge window of the detector. Warning:
- Spark plug cap; 2. Spark plug

Do not touch any connection part of the detector lead.
Keep away from combustible gases or liquids to avoid accidents caused by sparks.
Spark plug cap
- Unscrew the spark plug cap. Check the spark plug cap for damage. Replace it if necessary.
- Install the spark plug cap.
Flywheel maintenance
- Remove the flywheel nut using the flywheel gripper; Remove the flywheel using the flywheel puller.
- Check whether the flywheel is damaged and whether the permanent magnet is firm. Replace it if necessary.
Check engine startup switch
Check the conductivity of the engine startup switch. If it is not conductive, replace it.
Note:
See wiring diagram for startup switch status,
Check engine stop switch
Check the conductivity of the engine stop switch. If it is not conductive, replace it.
Remove the locking plate: Conducting
Install locking plate: Non-conducting
Press the button: Conducting
Detection of starting relay
- Connect the brown lead to the positive electrode of the battery.
- Connect the black lead to the negative electrode of the battery.
- Check the conductivity between relay terminals. If it is not conductive, replace the relay.
- Disconnect the lead connection with the battery and check the conductivity between the relay terminals. If it is conductive, replace the relay.
Detection of magneto coil
Measure the peak voltage of magneto coil (between green wires).
Use digital multimeter and peak voltage adapter to measure the peak output voltage of the coil. If it is lower than the specified value, replace the magneto coil.

| Peak voltage of magneto coil | 1500 r/min (no-load) 3500 r/min (no-load) | 47.2V 106V |
|---|

Detection of rectifier regulator
Measure the peak voltage (DC) of the rectifier regulator.
Open the rectifier output (red wire and black wire) and use a digital multimeter to measure the voltage between the red wire and black wire at the rectifier regulator output.
If it is lower than the specified value, check the peak output voltage of magneto coil. If the peak output voltage of magneto coil is higher than the specified value, replace the rectifier regulator.
| Peak voltage of rectifier regulator | 1500 r/min (no-load) 3500 r/min (no-load) | 41.9V 99.8V |
|---|
Use fault diagnosis tester
When the engine is running, if the fault indicator on the bottom cover is always on/buzzer is always on, it indicates that there is a fault in the engine. At this time, connect the fault diagnosis tester with the corresponding detection port on the engine, and display the running parameters and fault codes of the engine on the mobile phone through the APP. Then check the fault code table to determine the engine fault and replace the faulty electrical components.

Fault code table
| Fault type | Fault item | Code |
|---|---|---|
| Intake pressure fault | Short circuit to ground or open circuit of intake pressure sensor line | 107 |
| Intake pressure fault | Short circuit to high level of intake pressure sensor line | 108 |
| Intake temperature fault | Short circuit to high level of intake temperature sensor line | 112 |
| Intake temperature fault | Short circuit to ground or open circuit of intake temperature sensor line | 113 |
| Water temperature fault | Short circuit to ground of coolant temperature sensor line | 117 |
| Water temperature fault | Short circuit to high level of coolant | 118 |
| temperature sensor | ||
|---|---|---|
| Throttle fault | Short circuit to ground of throttle position sensor | 122 |
| Throttle fault | Short circuit to high level of throttle position sensor | 123 |
| Oxygen sensor fault | Short circuit to ground of oxygen sensor | 131 |
| Oxygen sensor fault | Short circuit to high level of oxygen sensor | 132 |
| Fault type | Fault item | Code |
|---|---|---|
| Oxygen sensor heating fault | Oxygen heater fault | 135 |
| Fuel injector fault | Cylinder 1 nozzle line fault | 201 |
| Fuel injector fault | Cylinder 2 nozzle line fault | 202 |
| Fuel injector fault | Cylinder 3 nozzle line fault | 203 |
| Fuel injector fault | Cylinder 4 nozzle line fault | 204 |
| Fuel pump fault | Oil pump relay fault | 230 |
| Crankshaft position sensor fault | Signal interference of crankshaft position sensor line | 336 |
| Crankshaft position sensor fault | No signal of crankshaft position sensor line | 337 |
| Ignition coil fault | 1. Cylinder ignition coil fault | 351 |
| Ignition coil fault | 2. Cylinder ignition coil fault | 352 |
| Ignition coil fault | 3. Cylinder ignition coil fault | 353 |
| Idle fault | Excessive idle speed fault | 507 |
| Idle fault | Low idle speed fault | 506 |
| System voltage fault | Low system voltage | 562 |
| System voltage fault | High system voltage | 563 |
| Fault indicator | Fault indicator fault | 650 |
| Oil pressure fault | Short circuit to ground of oil pressure sensor line | 523 |
| Oil pressure fault | Short circuit to high level of oil pressure sensor | 522 |
| Carbon canister solenoid valve fault | Short circuit to ground of carbon canister solenoid valve | 443 |
| Main relay fault | Main relay fault | 685 |
Fuel system
Precautions
Fuel oil is a highly flammable and volatile liquid, and fuel oil leakage can cause fire and explosion.
Do not attempt to start the engine until the fuel system components are connected or installed. After completing all maintenance steps, apply pressure to the fuel system for a short time to check for leakage.



Release the fuel pressure in the fuel line
Before the maintenance and inspection of the fuel system, please release the fuel pressure in the fuel line; Avoid accidents caused by high-pressure fuel injection during maintenance.
- Connect the pressure gauge with the pressure relief pipe to the oil pump detection valve of the electric fuel pump;
- Oil pump detection valve
- Insert the pressure relief pipe into a suitable container;

Note:
Do not release the pressure directly, The fuel will be discharged while pressure is released, Fuel spraying may cause accidents and violate local emission regulations.
- Press the pressure relief button to release the pressure until the pressure in the electric fuel pump is balanced with the outside world.
Removal and inspection of fuel joint
- Remove the bolts securing the fuel joint.
- Remove the fuel joint.
- Check the fuel joint for cracks or damage.
- Connect a vacuum manometer to the fuel joint outlet.
- Check whether the negative pressure can be maintained for more than 10 seconds under the specified pressure. Replace it if necessary. Specified pressure: 50kPa
Removal and inspection of fuel pump
- Remove the bolts securing the fuel pump.
- Remove the fuel pump.
- Connect a vacuum manometer to the fuel pump inlet.
- Plug the outlet of the oil pump with your fingers and apply the specified positive pressure. Check for air leakage. Specified pressure: 50kPa
- Apply a specified negative pressure. Check for air leakage. Specified pressure: 30kPa
- Connect a vacuum manometer to the fuel pump outlet.
- Plug the inlet of the oil pump with your fingers and apply a specified negative pressure. Check for air leakage.
- If necessary, disassemble the oil pump and check it.
- Remove the 4 bolts and separate the fuel pump cover and from the fuel pump seat.
- Remove the valve plate screw from the fuel pump body and remove the valve plate.
- Press down the plunger and diaphragm and rotate the fuel pump seat to align the notch with the groove on the plunger. Remove the roller pin.
- Check whether there are cracks in the diaphragm, whether the rivet is loose, and whether the valve plate is damaged. Replace it if necessary.
- According to steps 8-10, assemble the oil pump in reverse sequence.
Specified pressure: 50kPa


Filter inspection
Check whether the filter screen is blocked or there are sundries in it, and check whether the filter bowl is damaged or leaked.
If necessary, clean it with gasoline or replace it.
Note:
Before reassembling the filter bowl, apply lubricating oil to the O-ring.
1. Oil filter lid
2. Filter screen

Disassembly and inspection of electric fuel pump
Disassembly of electric fuel pump
- Loosen the oil drain screw of the oil cup and drain the fuel in the oil cup into a suitable container.
- Remove the fuel pipe and cooling water line and disconnect the wiring harness.
- Remove the mounting screws of the electric fuel pump and remove the electric fuel pump from the engine.
- Disconnect the pipeline connection between the fuel cooler and the electric fuel pump and remove the fuel cooler.
- Remove 5 cross recessed pan head screws (M4× 16) and the electric fuel pump body assembly.
- Pull off the oil pump assembly and disconnect the oil pump joint assembly;
- Check and clean the oil pump filter screen on the oil pump assembly;
- Check the rubber sleeve at the oil pump outlet, and replace it if it is aged, damaged or cracked;
- Loosen the screw for fixing the float pin and remove the float;
- Remove the baffle; (if necessary)
- Check and clean the oil cup assembly of electric fuel pump;
- Loosen the fixing screw of the pressure valve pressure plate and remove the pressure regulating valve;
- Check the O-ring of pressure regulating valve; Replace it if necessary;

- After inspection, clean the parts and install the electric fuel pump in reverse order of disassembly;
Note: Use a new oil cup sealing ring; The screws should be tightened according to the specified torque!
Inspection of fuel pipe and fuel filter
- Check whether the fuel pipe is damaged; If so, replace it;
- Check whether the high-pressure fuel filter is cracked and whether the fuel flows smoothly; Replace it if necessary.
Check the fuel common rail
Check the fuel common rail for leakage or cracking, and replace it if necessary.
Engine
Precautions
In order to avoid accidental start during engine maintenance, please take adequate protective measures to disconnect the ignition system. For example, remove the engine stop safety line from the emergency stop switch assembly, remove the spark plug cap from the spark plug, etc.







Piston slideway flywheel gripper and flywheel puller Valve spring compressor kit



Clearance gauge Oil filter spanner

Check the compression pressure
- 1 . Start the engine, warm it up for 5 minutes, and then shut it down.
- 2 . Remove the engine stop safety line.
- 3 . Remove the spark plug and connect the pressure gauge to the spark plug hole. Note:
Before removing the spark plug, clean the pit where the spark plug is installed with compressed air to prevent dust or other sundries from entering the cylinder.
- 4 . Fully open the throttle, turn the crankshaft using the starter or start motor, and check the cylinder pressure when the reading on the pressure gauge is stable.
Note:
For the control box in use, remove the throttle linkage, open the carburetor throttle lever fully by hand, and check the pressure.
- 5 . If the detected pressure is lower than the specified value or there is a difference between cylinder, add a small amount of oil into the cylinder and then detect it again. Compression pressure: 840 kPa
Note:
If the cylinder pressure continues to increase, check whether the piston and piston ring are damaged. Replace it if necessary.
If cylinder pressure does not increase, check valve clearance, valve, valve seat, cylinder liner, cylinder head and cylinder head gasket. Adjust or replace them if necessary.
The outboard motor is equipped with an automatic decompressor, so the data cannot be very accurate.
Check oil pressure
- Start the engine, warm it up for 5 minutes, and then shut it down.
- Remove the oil pressure switch and connect a pressure gauge.
Note:
Use a pressure gauge with 1/8 pitch thread adapter.
- Test oil pressure Oil pressure (reference data): 230kpa (60℃, 950±50 r/min)
Special tool
Remove the engine
- Open the top cover.
- Remove the flywheel cover.
- Remove the throttle cable
- Remove carburetor.
- Remove the flywheel using a special tool.

Flywheel gripper and flywheel puller
- Remove the semicircular key.
- Disconnect the engine stop switching line and ground wire.
- Remove cable connector.
- Remove the magneto coil.
- Disconnect the wires of the battery, starting motor, starting relay, warping relay, control box connector and other electrical components, disconnect grounding wire, disconnect water pipe.
- Remove the high voltage ignition coil, ECU device, ignition coil and spark plug.
- Remove the bolts connecting the engine and the water unit.
- Lift the engine and remove the locating pin.
Pulley and timing belt
- Turn the flywheel clockwise. Align the mark '1" on the driven pulley with the mark "▼" on the cylinder head.
Note:
Do not turn the flywheel counterclockwise, or it will damage the valve system.
- Remove the timing belt from the driven pulley side.
Note:
Do not turn the pulley when the timing belt is not installed, otherwise the valve system will be damaged.
- Remove the driven pulley bolt, remove the driven pulley and semicircular key.
Note:
Remove the driven pulley bolt with the flywheel gripper.
Do not turn the camshaft when loosening the timing pulley.
- Remove the timing pulley washer, timing pulley and semicircular key.
- Check pulley and timing belt for cracks, damage or wear. Replace it if necessary.
- Install the semicircular key and driven pulley. Align the mark '1" on the driven pulley with the mark "▼" on the cylinder head. Then
temporarily tighten the driven pulley bolt.
Note:
Do not turn the pulley when the timing belt is not installed, otherwise the valve system will be damaged.
- Install the semicircular key and timing pulley. Align the notch mark on the timing pulley with the mark "▼" on the engine body.
- Install a new timing belt with the timing belt part number upright.
Note:
Do not twist, rotate or bend the timing belt, otherwise it will be damaged.
Do not pour oil or lubricating oil on the timing belt.
Do not turn the pulley counterclockwise, or it will damage the valve system.
- Install the cover plate of the timing pulley and temporarily tighten timing pulley nut.
- Turn the timing pulley clockwise for 2 turns to eliminate the slack of the timing belt. Check whether the alignment marks are aligned.
- Tighten the bolts and nuts.
Seating torque: Driven pulley bolt 38 Nm
Note:
Remove the driven pulley bolt with the flywheel gripper.
Tighten the timing pulley nut using a special socket spanner for timing pulley nut.
Disassembly and inspection
Cylinder cover
Disassembly
- Remove cylinder head cover bolts.
- Remove the cylinder head bolts in reverse order according to the numerical symbols on the cylinder head.
- Remove the cylinder head, and then remove the oil pump.
- Remove the rocker shaft, spring and rocker arm assembly.
- Note:
Before removing the rocker shaft, loosen the lock nut and adjust the screw to the relaxed state.
- Remove the intake and exhaust valve using the valve spring compressor.

Valve and valve guide
- Check the width of valve sealing surface; If it is not within the prescribed scope, Trim the valve seat ring.
Width of sealing surface:
| Intake valve | 1.84 ~ 2.97mm |
|---|---|
| Exhaust valve | 1.98 ~ 3.11mm |
- Check the valve edge thickness T; Replace the valve if it does not meet the specified value.
Valve edge thickness:
| Intake valve | 0.6 ~ 1.0mm |
|---|---|
| Exhaust valve | 0.7 ~ 1.1mm |

- Check valve stem diameter. If it is not within the prescribed scope, replace the valve. Valve stem diameter:
- Check valve stem roundness. If it is beyond the limit, replace the valve.
- Check the inner diameter of the valve guide.
| Intake valve | 5.48 ~ 5.49mm |
|---|---|
| Exhaust valve | 5.46 ~ 5.47mm |
Valve stem roundness limit: 0.03mm
Valve guide inner diameter: 5.50
~ 5.51 mm
Note:

When replacing the valve, be sure to use new valve guide and valve oil seal.
Valve spring
- Check the free length of valve spring; Replace it if it is less than the specified value.
- Check the inclination of the valve spring; Replace it if it is beyond the limit.
Free length: 40.0 mm
Minimum free length: 38.4 mm
Inclination limit: 1.7 mm
Valve rocker and rocker shaft
- Check the contact surface of valve rocker and rocker shaft for wear. Replace them if necessary.
- Measure whether the inner diameter of valve rocker and outer diameter of rocker shaft meet the specified values. Replace it if necessary.
Inside diameter of valve rocker: 16.000
~ 16.018 mm
Outside diameter of rocker shaft: 15.73
~ 15.84 mm
Camshaft
- Check the cam dimensions.
Replace the camshaft if necessary.
| Cam height | Inta ke | 30.83~31.09mm |
|---|---|---|
| Cam height | Exh aust | 30.83~31.09mm |
| Diameter of base circle | Diameter of base circle | 25.90~26.10mm |
- Check camshaft roundness. Replace it if necessary.
- Check camshaft journal diameter and the inner diameter of cylinder head shaft hole. Replace it if necessary.
- Calculate the camshaft oil clearance c (c=b-a) and replace it if it does not meet the specified value.
Roundness limit: 0.03mm

Camshaft journal: 36.935~36.955mm
Inner diameter of cylinder head shaft hole b: 37.000~37.025 mm
Camshaft top: 0.06~0.10 mm
Centre and rear part of camshaft: 0.05~0.09 mm
Note:
The camshaft and cylinder head need to be replaced together.
Check the oil pump
- Remove the screw fixing the oil pump and remove the oil pump.
- Open the oil pump cover and check the oil pump rotor clearance as shown. If it does not meet the specified value, replace it.
a
b

| Clearance a between outer rotor and shell | 0.09~0.15mm |
|---|---|
| Clearance b between outer rotor and inner rotor | 0.01~0.10mm |
| Clearance c between rotor and cover | 0.03~0.08mm |
Joint surface of cylinder head and engine body
- Remove carbon deposits from combustion chamber and check for damage.
- Check the warpage of the joint surface with a ruler and a clearance gauge. If it does not meet the specified value, replace it.
Cylinder head buckling limit: 0.03mm
Replace valve guide
- Knock off the valve guide in the direction of the combustion chamber.
- Knock in the new valve guide from the top surface of the cylinder head.
Note:
Apply oil to the surface of the valve guide before installation.
- Hinge the inner diameter of the guide to the specified value with a reamer.
Valve guide inner diameter: 5.50
~ 5.518mm
Note:
Do not rotate the reamer counterclockwise when taking it out.
Check valve seat ring
- Remove carbon deposit from the valve.
- Coat a thin layer of dye evenly on the sealing surface of the valve seat ring.
- Grind the valve on the valve seat with the valve grinding tool.
- Measure the width of valve sealing surface.
Dye will stick to the valve sealing surface.
If the valve and valve seat ring fit incorrectly or the sealing surface width does not meet the specified value, trim the valve seat.
If the contact surface is uneven, replace the valve guide.
Width of intake and exhaust valve sealing surface: 0.9 ~ 1.1mm
Trim the valve seat ring
- Trim the valve with a 45° valve seat ring cutter and adjust the width of the sealing surface.
Turn the cutter clockwise until the surface of the seat ring is smooth.
- If the valve sealing surface is too wide and in the middle of the valve surface, trim the top edge of the seat ring with a 30° cutter and trim the bottom edge of the seat ring with a 60° cutter, and adjust the width of the sealing surface.
- If the valve sealing surface is too narrow and at the top edge of the valve surface, trim the top edge of the seat ring with a 30° cutter, and adjust the width of the sealing surface with a 45° tool (if any).
- If the valve sealing surface is too narrow and at the bottom edge of the valve surface, trim the bottom edge of the seat ring with a 60° cutter, and adjust the width of the sealing surface with a 45° cutter (if any).
- Apply a thin layer of abrasive evenly to the valve seat ring, and grind the valve with a



valve grinding tool.
- Remove the residual abrasive.
- Check the width of valve sealing surface again.
Note:
Do not excessively cut the valve, and turn the cutter evenly with a downward force of
Do not stick the abrasive on the valve stem and valve guide.
Install the valve
- Install a new valve oil seal and apply engine oil to the valve guide.
- Install the valve, valve spring plate, valve spring and spring seat in sequence.
- Compress the valve spring with the valve spring compressor and install the valve spring retainer.
- Tap the valve spring seat with a plastic or rubber hammer to secure the retainer.
Assemble cylinder head
- Install a new oil seal with the special tool.
- Fit the camshaft into cylinder head in the oil pump direction.
- Check whether the spline position faces the cylinder joint surface. If necessary, make adjustments.
- Install the rocker arm assembly, spring and rocker shaft.
- Assemble the oil pump.
Note:
Make sure the mark on the outer rotor faces the oil pump cover
- Align the oil pump drive shaft and camshaft pins and install the oil pump.
Note:
Before installing the oil pump, make sure the oil path is clear and fill the oil pump with
Crankcase Disassembly
- Remove the oil filter using a special tool.
Note:
Place a cloth under the oil filter.

Filter spanner
- Remove the bolts in reverse order according to the serial number on the edge of the screw hole on the exhaust cover plate.

40 ~ 50N.
oil.
- Remove thermostat cover, exhaust cover, gasket and locating pin. Check the exhaust cover for cracks, deformation or corrosion. Replace it if necessary.
- Remove the bolts on the body in reverse order according to the serial number on the edge of the screw hole on the engine base, and remove the engine base.
- Remove the connecting rod bolts and connecting rod cover, remove the crankshaft, and then remove the connecting rod and piston assembly.
- Remove piston pin clamp spring with pliers, then remove the piston pin and piston.
- Remove the oil seal, locating pin and bearing bush.
Piston
- Measure the outside diameter of piston at the specified measuring point. If it does not meet the specified value, replace it.
- Check the inner diameter of piston pin hole. If it does not meet the specified value, replace it. Inner diameter of piston pin seat: 16.002 ~ 16.008 mm
Diameter of piston: 64.930
~ 64.945 mm
Measuring point○
a : 3 mm
Cylinder bore
- Measure the piston outer diameter at specified measuring points○ 1 ○ 2 ○ 3 . At each measuring point, measure the diameters parallel to the crankshaft directions D1,
D3 and D5 and perpendicular to the crankshaft directions D2, D4 and D6.
Height of measuring point: ○
1 20 mm;
○ 260 mm;
○ 3100 mm
Cylinder bore: 65.000
~ 65.013 mm

- Calculate the taper limit and roundness limit. If it exceeds the specified value, replace the crankcase.
Taper limit: 0.08 mm (D1-D5, D2-D6)
Roundness limit: 0.05 mm (D2-D1, D6-D5)
Outside diameter of piston pin
Check the outside diameter of piston pin; If it does not meet the specified value, replace it. Outside diameter of piston pin: 15.965 ~ 15.970 mm
Piston ring
- Check the sectional dimensions of piston ring. If it does not meet the specified value, replace it.
- Push the piston ring into the cylinder in parallel with the piston to the specified measuring point (20mm from the joint surface).
| Thickness | Section width | |
|---|---|---|
| Top ring | 1.17 ~ 1.19mm | 2.39 ~ 2.41mm |
| Second ring | 1.47 ~ 1.49mm | 2.49 ~ 2.51mm |
| Oil ring | 2.34 ~ 2.46mm | 2.75mm |

- Measure the clearance of piston ring end face with a clearance gauge; If it does not meet the specified value, replace it.
End face clearance (during installation): Top ring 0.15
Second ring 0.30
~ 0.50 mm
Oil ring 0.20 ~ 0.70 mm
- Install the piston ring on the piston, and measure the clearance between the piston ring and the piston ring groove with a clearance gauge; If it does not meet the specified value, replace it.
Specified clearance: Top ring 0.02
~ 0.06 mm
Second ring is 0.02
~ 0.06 mm
Oil ring 0.04 ~ 0.18 mm
Inner diameter of connecting rod small end
Measure the inside diameter of the small end. If it does not meet the specified value, replace it.
Inner diameter of small end: 15.985
~ 15.998 mm
Connecting rod large end backlash
Measure the big-end backlash. If it does not meet the specified value, replace the connecting rod or crankshaft or both. Large end backlash: 0.05 ~ 0.22 mm
Check connecting rod bolts

- Check the thread diameter of the connecting rod bolt at the position shown in the figure.
- Calculate the diameter difference of two threads; If it does not meet the specified value, replace it.

Thread diameter difference of connecting rod bolt: 0 ~ 0.1 mm
Crankshaft
- Measure crankshaft main journal diameter, crank pin diameter and crank pin width. If they do not meet the specified value, replace the crankshaft.
- Check the crankshaft runout; If it exceeds the specified value, replace it.
| Diameter of crankshaft journal | 42.984~43.000mm |
|---|---|
| Crank pin diameter | 32.984~33.000mm |
| Crank pin width | 21.000~21.070mm |
~ 0.30 mm

Crankshaft runout limit: 0.04mm
Crank pin oil clearance
- Place a plastic clearance gauge on the crank pin and make it parallel to the crankshaft.
- Fit the connecting rod and bearing bush on the crank pin.
- Tighten the connecting rod bolts according to the specified torque.
- Remove the connecting rod and measure the compressed width of the plastic clearance gauge; If it exceeds the specified value, replace the connecting rod bearing bush.
Seating torque: First time 6 Nm
Second time 17 Nm
Oil clearance: 0.020
Note:
Do not turn the connecting rod until the measurement is completed.
Main journal oil clearance
- Clean the bearing bush, main journal, and the mounting surface of the engine body and engine base.
- Install the bearing bush and crankshaft to the engine body.
- Place a plastic clearance gauge on the main journal and parallel it to the crankshaft Note:
Do not place the plastic clearance gauge on the oil hole of the main journal.
- Install the bearing bush on the engine base and the engine base on the engine body.
- Tighten bolts with specified torque in the order of numerical symbols on the engine base.
Seating torque:
| First tightening | M8 | 15 Nm |
|---|---|---|
| Second tightening | M8 | 30 Nm |
| First tightening | M6 | 6 Nm |
| Second tightening | M6 | 12 Nm |
- Remove the engine base and measure the compressed width of each plastic clearance gauge; If it exceeds the specified value, replace the bearing bush.
Oil clearance: 0.012
Note:
Do not turn the crankshaft until the measurement is completed.
Body and engine base
~ 0.044mm
~ 0.052mm
- Check whether the engine body and base are cracked, damaged and corroded; If yes, replace it.
- Check the cooling water channel for grease content or blockage; If yes, clean it.
Reinstallation
Assemble piston connecting rod
Install piston, connecting rod, piston pin and piston pin clip clutch.
Note:
When installing, make sure that the mark on the connecting rod and the mark on the top of the piston are on the same side.
Installing the piston rings
- Install piston rings in the order of oil ring, second ring and top ring.
Note:
When installing the second ring, ensure that the mark faces the top of the piston.
- Position of piston ring notch Oil ring lower retaining ring 1 Oil ring elastic ring 2 Oil ring upper retaining ring 3 Second ring 4 Top ring 5
Installing piston
Install piston with piston slideway,
Make sure that the "UP" mark on the top of the piston faces the flywheel.
Note:
When installing, apply oil to the sides of the piston and piston ring.
Installing crankshaft
- 1.Install the bearing bush on the engine body.
Note:
Insert the raised part on the bearing bush into the groove of the corresponding part of the engine body.
- Install the crankshaft to the engine body and install the oil seal.
Note:
Apply oil on the inside of the oil seal before installation.
- Install the connecting rod cover to the connecting rod and tighten the bolts to the specified torque in two steps.
Seating torque: First time 6 Nm
Second time 17 Nm
Note:
Align the connecting rod cover with the mark on the connecting rod.
Apply oil to connecting rod bolts before installation.


Note:
Before installation, apply oil to the moving surface.
Apply oil to the bolts before installation.
- Install oil filter with special tools and tighten it at specified torque.
Seating torque: 18 Nm
Note:
Before installation, inject oil into the oil channel.
- Install exhaust cover plate, thermostat and thermostat cover plate.
Tighten them according to the specified torque twice in the order marked on the exhaust cover plate.
Assemble the engine
- Coat sealant on the joint surface of the engine base, and install the locating pin and the engine base. Tighten the bolts twice in the order marked on the base.
Seating torque:
| First tightening | M8 | 15 Nm |
|---|---|---|
| Second tightening | M8 | 30 Nm |
| First tightening | M6 | 6 Nm |
| Second tightening | M6 | 12 Nm |
Seating torque: First time 6 Nm
The first 12 Nm
- Install the locating pin, cylinder gasket and cylinder head assembly.
- Check the keyway position of semicircular key on the camshaft
- Tighten the cylinder head bolts to the specified value in 2 steps in the order marked on the cylinder head.
Specified torque:
| First tightening | M9 | 23 Nm |
|---|---|---|
| Second tightening | 46 Nm | |
| First tightening | 6 Nm | |
| Second tightening | M6 | 12 Nm |
Note:
It is strictly forbidden to use old cylinder head gaskets.
- Install the timing pulley, driven pulley, timing belt and breather pipe.
Note:
When installing the timing belt. Ensure that the markings on the driven pulley are aligned with the "▼" mark on the cylinder head; Ensure that the mark on the timing pulley is aligned with the mark "▼" on the body.
- Adjust valve clearance.
- Install the cylinder head cover and tighten the bolts in the order marked on the cylinder head cover.
- Install electrical system components in reverse order according to the removal sequence
- Connect the wires of the electrical system.
- Install fuel system.
About water
Top cover Disassembly schematic diagram

Disassembly and inspection
- Remove the sealing rubber strips.
- Remove the top cover screws.
- Remove the top cover.
- Remove the locking hook and the hook.
- Check the top cover for cracks or damage. Replace it if necessary.
- Check the sealing rubber strip for cracks or damage. Replace it if necessary.
- Check the top cover muffler cover for cracks or damage. Replace it if necessary.
- Check the locking hook and the hook for cracks, deformation or damage. Replace it if necessary.
Bottom cover
Disassembly schematic diagram

Back operation model


Disassembly and inspection
- Remove rubber bulkhead, corrugated sheath and throttle cable sheath. Remove the ignition lead assembly.
- Remove the bolts fixing the small cover plate of the bottom cover, remove the small cover plate of the bottom cover, and remove the square rubber sealing strip. Remove the retainer of the outlet and the rectangular rubber bulkhead.
- Remove the top cover locking handle screw, and remove the top cover locking handle and top cover locking block.
- Remove the top cover locking handle nylon sleeve A and the top cover locking handle nylon sleeve B.
- Remove corrugated washer.
- Disconnect the throttle control cable and remove the throttle actuator. Remove the control cable retainer. (Back operation) Remove the control cable connector A and remove the throttle actuator. Remove the control cable retainer. (Front operation)
- Remove the shift lever support, shift lever assembly and brake rocker arm. Remove the gear spring plate.
- Check the bottom cover for cracks or damage. Replace it if necessary.
- Check the top cover locking handle and the top cover locking block for cracking or damage. Replace it if necessary.
- Check the corrugated washer and locking handle nylon sleeve A for cracking or damage. Replace it if necessary.
- Check whether the throttle actuator is cracked or damaged. Replace it if necessary.
- Check the shift lever assembly for bending deformation or damage. Replace it if necessary.
- For back-operation and electric-start model, check whether the rocker arm of microswitch is worn; Check the conductivity of the microswitch. Check whether the steering linkage is bent or deformed. Replace it if necessary.
Steering handle
Disassembly schematic diagram

Disassembly and inspection
- 1 . Remove handle bracket, shift handle and steering handle.
- 2 . Remove the throttle push-pull cable assembly.
- 3 . Remove the cotter pin and remove the resistance adjustment knob.
- 4 . Remove the throttle grip.
- 5 . Remove throttle retaining plate and throttle lever.
- 6 . Remove the engine emergency stop switch.
- 7 . Check whether the shift linkage is bent and deformed. Replace it if necessary.
- 8 . Check the steering handle for cracks or damage. Replace it if necessary.
- 9 . Check the handle anti-wear ring and wave washer for cracks or damage. Replace it if necessary.
- 10 . Check whether the cable in the throttle push-pull cable assembly is worn or broken. Replace it if necessary.
- 11 . Check whether the throttle lever is bent or damaged. If yes, replace it.
- 12 . Check the conductivity of engine emergency stop switch ; If it does not conform to the standard, replace it.
Remove the locking plate: Conducting
Install locking plate: Non-conducting
Press the switch button: Conducting

Water unit and bracket




Disassembly and inspection of bracket
- Remove the left and right absorber covers, and remove the left and right absorbers and double-hole absorber fixing nuts.
- Remove the water unit, oil pan and exhaust manifold seat as a whole from the bracket
- Remove bracket clamping nut and clamp bracket twin-headed threads.
- Disconnect the grounding cable and remove the clamp bracket.
- Remove the cotter pin Φ2×12 and circlip 9, and remove the long shaft of the locking frame and the short shaft of the outer frame.
- Remove the inner and outer frames of the support frame.
- Pull out the steering carrier assembly and remove the ring gasket, bushing and O-ring.
- Check the rotary bracket and clamp bracket for cracking or damage. Replace it if necessary.
- Check the bushing and ring gasket; Replace it if damaged or cracked.
- Check the support frame assemblies A & B for deformation or damage. Replace it if necessary.
- Check the left and right absorber rubber for aging, cracking, or degumming. Replace it if necessary.
Disassembly and inspection of water unit
- Drain the oil.
- Remove the mounting bolts on the water and underwater, and remove the water unit.
- Remove the exhaust manifold block and oil pan.
- Remove the coarse filter assembly and coarse filter bracket from the exhaust manifold seat.
- Remove the exhaust manifold, drain screw, rubber sleeve of the oil drain hole, exhaust manifold rubber sleeves A&B and exhaust manifold block from the oil pan.
- Remove the double-hole absorber, exhaust partition, round rubber ring of water pipe and water pipe.
- Check the water unit housing and oil pan for cracking or damage. Replace it if necessary.
- Check the exhaust manifold for cracking or damage. Replace it if necessary.
- Check the exhaust pipe sealing ring and exhaust manifold rubber sleeves A&B for aging and cracking. Replace it if necessary.

Disassemble
- Completely warp the outboard motor upward, and push it in the warping limit shaft to support the outboard motor.
- Remove the circlip 9, and remove the warping hinge pin.
- Remove bolts and hydraulic positioning shaft.
- Remove the manual cylinder assembly
Manual warping device
Disassembly schematic diagram

Disassemble
- Completely warp the outboard motor upward, and push it in the warping limit shaft to support the outboard motor.
- Remove the circlip 9, and remove the warping hinge pin.
- Remove bolts and hydraulic positioning shaft.
- Remove the manual cylinder assembly
Check the oil level.
- Position the hydraulic warping device vertically and fix it.
- Connect the lead of the warping motor of the hydraulic warping device to the battery.
- Extend the push rod completely, remove the oil screw, and observe the oil level.
Note:
The oil level should be at the edge of the oil hole,

- Oil drain screw
- If necessary, add oil to the edge of the oil hole.
- Install the oil drain screw and tighten it.
Specified torque: 6.5 Nm
Exhaust the air in the oil line of the hydraulic warping device. After adding oil, discharge the excess air in the oil.
- Connect the lead of the warping motor of the hydraulic warping device to the battery.
- Extend the push rod completely.
- Exchange the positive and negative wire connections.
- Completely compress the push rod.
- Repeat steps 1
4 to make the push rod move up and down 45 times. - Extend the push rod completely, remove the oil screw, and observe the oil level.
- If necessary, repeat the above steps until the oil level is correct.
- Install the oil drain screw and tighten it.
Specified torque: 6.5 Nm
If the hydraulic warping device is installed on the outboard motor and exhausting is required, please follow the following steps.
- Turn the manual valve counterclockwise until it cannot turn.
- Manual valve.
- Tilt the outboard motor completely upward, and then lower it downward by its own gravity; Repeat 4~5 times.
- Turn the manual valve clockwise until it cannot turn.
- Wait for 5 minutes to stabilize the oil.
- Press and hold the warping switch until the outboard motor is completely warped.
- Wait for 5 minutes to stabilize the oil.
- Remove the oil drain screw and observe the oil level.
- If necessary, repeat the above steps until the oil level is correct.
- Install the oil drain screw and tighten it.

Specified torque: 6.5 Nm
Underwater part
Disassembly schematic diagram


Disassembly and inspection
- Remove the water pipe.
- Remove the pump housing.
- Remove the impeller and pump inner shell.
- Remove the semicircular key and outer plate.
- Check the pump casing and outer plate for cracks, distortions or damage. Replace it if necessary.
- Check the pump inner shell and impeller for cracking, deformation, burning or wear. Replace it if necessary
- Drain gear oil. Remove the cotter pin.
- Place a piece of wood between the anti-swirl baffle and the propeller to prevent the propeller from rotating freely. Remove the slotted hexagon nut, anode and water inlet.
- Remove the propeller and cushion block.
- Remove the anode.
- Remove the housing cover of the underwater unit. Remove the reverse gear and shim, and remove the oil seal.
- Remove the propeller shaft assembly.
- Remove the shift plunger.
- Remove the clutch ring, clutch pin and claw clutch. Remove the clutch spring.
- Remove oil seal housing A.
- Remove the pinion nut using an internal spline wrench and remove the drive shaft.
- Remove the shift cam and forward gear.

Remove the cover plate of the shift cam and remove the shift cam. Remove the forward gear (CD/CT)
- Remove the needle bearing from the underwater unit.
- Remove the oil seal of oil seal housing A and remove the bearing on the forward gear.
Propeller shaft and clutch block
- Check the claw clutch; If broken or damaged, replace it.
- Check the propeller shaft; Replace it if worn or bent.
Install the claw clutch
- Fit the clutch spring into the hole at the tail of the propeller shaft.
- Install the claw clutch. Mark "F" or "●" towards forward gear. Fix the clutch pin.
- Fix the clutch ring and shift plunger.

Housing cover of underwater unit
- Check the bearing for rust and whether there is noise during rotation; If so, replace it.
- Remove the bearing and oil seal with bearing puller.
Note:
Do not remove the bearing unless it needs to be replaced.
- Remove the needle bearing with special tool.
Note:
When reinstalling the oil seal and needle bearing, please use new parts to replace them.
- Clean the housing cover with a soft brush and solvent.
- Check the housing cover; Replace it if cracked or damaged.
Install the oil seal and bearing of the housing cover
- Install the oil seal.
- Fit the new bearing on the reverse gear.
Note:
Use special tools to install the oil seal and bearing.
Pay attention to the installation direction and depth.
Make sure that the manufacturer's mark of the bearing faces the reverse gear.
Mounting depth:
Underwater unit housing cover bearing installation tool
| Needle roller bearing | Needle roller bearing | 31.0~31.5mm |
|---|---|---|
| Oil seal | Depth 1 | 13.0~13.5mm |
| Oil seal | Depth 2 | 6.0~6.5mm |


Underwater unit housing cover oil seal installation tool
- Install reverse gear and shim.
Underwater unit housing cover needle bearing installation tool

Note:
Shim adjustment is required when installing new reverse gears and bearings.
Drive shaft
Check the drive shaft for bending or wear. Replace it if necessary.
Shift cam
Check whether the shift cam is worn or deformed. Replace it if necessary.
Gear
Check the forward gear, reverse gear and pinion for wear or damage. Replace it if necessary.
Forward gear bearing
Check whether the bearing is corroded and whether there is noise when rotating; Replace it if necessary.
Note:
Do not remove the bearing unless it needs to be replaced.
When installing a new bearing, it is required to adjust the shim.
Check the housing of the underwater unit
Check whether the housing of underwater unit is cracked or damaged, and check whether the cooling water inlet is blocked; Replace them if necessary.
Check the water pipe
Check the water pipe for corrosion or bending. Replace it if necessary.
Assemble the housing of the underwater unit
- Use special tools to install the needle bearing.
- Install the new forward gear bearing. (Replace it if necessary)
Needle bearing installation tool kit


Forward gear bearing jacket installation kit
- Install the oil seal for drive shaft seat.
- Install shift cam, gasket and pump housing A. Install forward gear, drive shaft, shim
Drive shaft seat oil seal installation tool kit

and pinion.
Note:
When installing a new drive shaft, it is required to adjust the shim.
- Tighten the pinion nut.
- Install the propeller shaft assembly.
- Install the underwater unit housing cover.
Specified torque: 95 Nm

Installation tool for housing cover assembly of underwater unit
- Check whether the gear shift is working properly.
- Install the water pump assembly.
- Install the anode and water inlet.
- Install the propeller and slotted hexagon nut, place a piece of wood between the anti-swirl baffle and the propeller,
- Tighten the nut according to the specified torque.
Specified torque: 35 Nm
Note:
If the groove on the nut is not aligned with the cotter pin hole on the propeller shaft, tighten the nut further until they are aligned.
Install the underwater unit
- Install the locating pin.
- Place the shift cam in the forward position. Install the underwater unit to the housing of the water unit and tighten the bolts to the specified value. Specified torque: 40 Nm
- Perform shift operation and check whether it is operating normally.
- Add gear oil with pressure filling device.
Selection of shim
When replacing the internal parts of the underwater unit or assembling a new underwater unit, it is required to adjust the shim.
Deviation value mark

The installation surface of the anode/heading tab of the underwater unit is engraved with
deviation value marks, which are F, R and P respectively; they represent the difference between the actual size and the theoretical size on the housing of the underwater unit. For example, the mark P is followed by +3, which means that the actual size is 0.03 mm more than the theoretical size; If no number is engraved after the deviation value, then P is regarded as 0.
Pinion shim
- Check the P value marked on the underwater unit.
- Attach the drive shaft to the special tool. Install the pinion and lock the pinion nut according to the specified torque.

Specified torque: 95 Nm
- Measure the clearance between special tool and pinion with stopper gauge Calculate the thickness T3 with the formula.
Formula: T3=M3
- (P/100)
- Shims that can be selected.
0.10, 0.12, 0.15, 0.18, 0.3, 0.4, 0.5 mm
Note:

The thickness of the shim can be 0~0.05 thicker than T3, and choose the closest size.
Forward gear shim
- Check the F value marked on the underwater unit.
- Turn the outer ring of the forward gear bearing so that the rollers fall completely into the bearing outer sleeve.
- Measure the bearing height and calculate the thickness T1 with the formula.
Formula: T1=22.75 + (F/100) - M1
Note:
When measuring the thickness, three points are measured. Take the average value.
- Shims that can be selected. 0.10, 0.12, 0.15, 0.18, 0.3, 0.4, 0.5 mm
Note:

The thickness of the shim can be 0~0.05 thinner than T1, and choose the closest size.
Reverse gear shim
- Check the R value marked on the underwater unit.
- Measure the dimension M2 as shown in the figure with a depth gauge:

3. Formula: T2=108.25 +(R)/100-M2
4. Shims that can be selected.
0.10, 0.12, 0.15, 0.18, 0.3, 0.4, 0.5 mm
Note:
The thickness of the shim can be 0~0.05 thinner than T2, and choose the closest size.
Common faults and solutions
| Fault type | Fault cause | Solution |
|---|---|---|
| Engine fails to start | There is no fuel in the fuel tank Contaminated or obsolete fuel oil | Fill the fuel tank with clean new fuel |
| Fuel filter blocked | Replace the fuel filter | |
|---|---|---|
| Fuel pump failure | Overhaul or replace it | |
| Vent screw of fuel tank cap not loosened | Loosen the vent screw | |
| The spark plug is contaminated or the model is incorrect | Check the spark plug. Clean it or replace with the correct spark plug | |
| Incorrect installation of spark plug cap | Check and reinstall the spark plug cap | |
| Ignition circuit failure | Check the wiring. Tighten the loose wire and replace the old or broken wire. | |
| Ignition component failure | Replace it | |
| The engine stop safety line is not connected to the emergency stop switch assembly. | Connect the line to the switch | |
| Internal parts failure of the engine | Repair it | |
| Engine abnormal | The spark plug is contaminated or the model is incorrect | Clean it or replace with the correct spark plug |
| Engine abnormal | Fuel system blocked | Check the fuel line for extrusion, entanglement or blockage |
| Engine abnormal | Fuel oil polluted or obsoleted | Fill the fuel tank with clean new fuel |
| Engine abnormal | Fuel filter blocked | Replace the fuel filter |
| Engine abnormal | Incorrect spark plug gap | Adjust the gap to the specified value |
| Engine abnormal | Ignition circuit failure | Check the wiring. Tighten the loose wire and replace the old or broken wire. |
| Engine abnormal | Incorrect engine oil grade | Change it to the specified oil grade |
| Engine abnormal | Thermostat failure | Replace it |
| Engine abnormal | Fuel pump failure | Replace it |
| Engine abnormal | Vent screw of fuel tank cap not loosened | Loosen the vent screw |
| Engine abnormal | The fuel joint is not connected correctly | Connect it correctly |
| Engine abnormal | Pull out the choke handle and return it to its original position | |
| Engine abnormal | The angle of the outboard motor is too high | Return it to its normal running position |
| Propeller damaged | Repair or replace the propeller | |
| Incorrect trim angle | Adjust the trim angle to the appropriate angle | |
| Incorrect installation height of outboard motor | Adjust it to the correct height | |
| The bottom of the ship is polluted by underwater organisms | Clean the bottom of the ship | |
| Gear box twined by aquatic plants or foreign matters | Remove the foreign matters and clean it | |
| The engine is weak. | The spark plug is contaminated or the model is incorrect | Clean it or replace with the correct spark plug |
| The engine is weak. | Fuel system blocked | Check the fuel line for extrusion, entanglement or blockage |
| The engine is weak. | Fuel filter blocked | Replace the fuel filter |
| The engine is weak. | Fuel oil polluted or obsoleted | Fill the fuel tank with clean new fuel |
| The engine is weak. | Incorrect spark plug gap | Adjust the gap to the specified value |
| The engine is weak. | Ignition circuit failure | Check the wiring. Tighten the loose wire and replace the old or broken wire. |
| The engine is weak. | Ignition component failure | Replace it |
| The engine is weak. | Incorrect engine oil grade or excessive oil | Change to the specified oil grade or add it to the proper position of the oil dipstick |
| The engine is weak. | Thermostat failure | Replace it |
| The engine is weak. | Fuel pump fault | Replace it |
| The engine is weak. | The fuel joint is not connected correctly | Connect it correctly |
| The engine is weak. | Incorrect spark plug specification | Replace it with the correct model |
| Excessive vibration of outboard motor | Propeller damaged | Repair or replace the propeller |
| Excessive vibration of outboard motor | Propeller shaft damaged | Replace it |
| Excessive vibration of outboard motor | Propeller twined by aquatic plants or foreign matters | Remove the foreign matters and clean it |
| Excessive vibration of outboard motor | Mounting bolts of outboard motor loosened | Tighten the bolts |
| Excessive vibration of outboard motor | Steering shaft loosened | Tighten the shaft |
| Excessive vibration of outboard motor | Steering shaft damaged | Replace |