Troubleshooting Parsun F20/F25 Outboard Engine

Q: Parsun F20/F25 carburetor outboard: Engine idles irregularly or stalls

Air vent screw on fuel tank is closed: Open air vent screw Carburetor adjustments are incorrect: Have serviced by your dealer Carburetor is clogged: Have serviced by your dealer Choke knob is pulled out: Return to home position Fuel filter clogged: Clean or replace with recommended type Fuel is contaminated or stale: Fill tank with clean, fresh fuel Fuel joint connection is incorrect: Connect correctly Fuel pump is damaged: Have serviced by your dealer Fuel system is obstructed: Check for pinched or kinked fuel line or other obstructions in fuel system Ignition wiring damaged or poorly connected: Check wires for wear or breaks. Tighten all loose connections. Replace worn or broken wires Motor angle is too high: Return to normal operating position Spark plug gap is incorrect: Inspect and adjust as specified Spark plug(s) fouled or of incorrect type.: Inspect spark plug(s). Clean or replace with recommended type Specified engine oil is not being used: Check and replace oil as specified Thermostat is faulty or clogged: Have serviced by your dealer Throttle valve adjustment is incorrect: Have serviced by your dealer

Q: Parsun F20/F25 carburetor outboard: Engine power loss

Air vent screw on fuel tank is closed: Open air vent screw Boat bottom is fouled with marine growth: Clean boat bottom Fuel filter is clogged: Clean or replace with recommended type Fuel is contaminated or stale: Fill tank with clean, fresh fuel Fuel joint connection is incorrect: Connect correctly Fuel pump has malfunctioned: Have serviced by your dealer Fuel system is obstructed: Check for pinched or kinked fuel line or other obstructions in fuel system Ignition parts have failed: Have serviced by your dealer Ignition wiring is damaged or poorly connected: Check wires for wear or breaks. Tighten all loose connections. Replace worn or broken wires Motor is mounted at incorrect transom height: Adjust motor to proper transom height Propeller is damaged: Repair or replace propeller Spark plug gap is incorrect: Inspect and adjust as specified Spark plug(s) are fouled or incorrect type: Inspect spark plug(s). Clean or replace with recommended type Specified engine oil is not being used: Check and replace oil as specified Specified spark plug(s) are not being used: Check and replace spark plug(s) as specified Thermostat is faulty or clogged: Have serviced by your dealer Trim angle is incorrect: Adjust trim angle to achieve most efficient operation Weeds or other foreign matter are tangled on gear housing: Remove foreign matter and clean lower unit

Q: Parsun F20/F25 carburetor outboard: Engine vibrates excessively

Motor mounting bolt is loose: Tighten bolt Propeller is damaged: Repair or replace propeller Propeller shaft is damaged: Have serviced by your dealer Steering pivot is damaged: Have serviced by your dealer Steering pivot is loose: Tighten it Weeds or other foreign matter are tangled on propeller: Remove and clean propeller

Q: Parsun F20/F25 carburetor outboard: Engine will not start (starter operates)

Engine inner parts are damaged: Have serviced by your dealer Engine stop switch lanyard is not attached: Attach lanyard Fuel filter clogged: Clean or replace with recommended type Fuel is contaminated or stale: Fill tank with clean, fresh fuel Fuel pump has malfunctioned: Have serviced by your dealer Fuel tank is empty: Fill tank with clean, fresh fuel Ignition parts are faulty: Have serviced by your dealer Ignition wiring damaged or poorly connected: Check wires for wear or breaks. Tighten all loose connections. Replace worn or broken wires Spark plug cap(s) fitted incorrectly: Check and re-fit cap(s) Spark plug(s) fouled or of incorrect type.: Inspect spark plug(s). Clean or replace with recommended type

Q: Parsun F20/F25 carburetor outboard: Starter will not operate

Shift level is not in neutral: Shift to neutral Starter components are faulty: Have serviced by your dealer

Question 1

Parsun F20/F25 carburetor outboard: Engine idles irregularly or stalls

Accepted Answer

Air vent screw on fuel tank is closed: Open air vent screw
Carburetor adjustments are incorrect: Have serviced by your dealer
Carburetor is clogged: Have serviced by your dealer
Choke knob is pulled out: Return to home position
Fuel filter clogged: Clean or replace with recommended type
Fuel is contaminated or stale: Fill tank with clean, fresh fuel
Fuel joint connection is incorrect: Connect correctly
Fuel pump is damaged: Have serviced by your dealer
Fuel system is obstructed: Check for pinched or kinked fuel line or other obstructions in fuel system
Ignition wiring damaged or poorly connected: Check wires for wear or breaks. Tighten all loose connections. Replace worn or broken wires
Motor angle is too high: Return to normal operating position
Spark plug gap is incorrect: Inspect and adjust as specified
Spark plug(s) fouled or of incorrect type.: Inspect spark plug(s). Clean or replace with recommended type
Specified engine oil is not being used: Check and replace oil as specified
Thermostat is faulty or clogged: Have serviced by your dealer
Throttle valve adjustment is incorrect: Have serviced by your dealer

Question 2

Parsun F20/F25 carburetor outboard: Engine power loss

Accepted Answer

Air vent screw on fuel tank is closed: Open air vent screw
Boat bottom is fouled with marine growth: Clean boat bottom
Fuel filter is clogged: Clean or replace with recommended type
Fuel is contaminated or stale: Fill tank with clean, fresh fuel
Fuel joint connection is incorrect: Connect correctly
Fuel pump has malfunctioned: Have serviced by your dealer
Fuel system is obstructed: Check for pinched or kinked fuel line or other obstructions in fuel system
Ignition parts have failed: Have serviced by your dealer
Ignition wiring is damaged or poorly connected: Check wires for wear or breaks. Tighten all loose connections. Replace worn or broken wires
Motor is mounted at incorrect transom height: Adjust motor to proper transom height
Propeller is damaged: Repair or replace propeller
Spark plug gap is incorrect: Inspect and adjust as specified
Spark plug(s) are fouled or incorrect type: Inspect spark plug(s). Clean or replace with recommended type
Specified engine oil is not being used: Check and replace oil as specified
Specified spark plug(s) are not being used: Check and replace spark plug(s) as specified
Thermostat is faulty or clogged: Have serviced by your dealer
Trim angle is incorrect: Adjust trim angle to achieve most efficient operation
Weeds or other foreign matter are tangled on gear housing: Remove foreign matter and clean lower unit

Question 3

Parsun F20/F25 carburetor outboard: Engine vibrates excessively

Accepted Answer

Motor mounting bolt is loose: Tighten bolt
Propeller is damaged: Repair or replace propeller
Propeller shaft is damaged: Have serviced by your dealer
Steering pivot is damaged: Have serviced by your dealer
Steering pivot is loose: Tighten it
Weeds or other foreign matter are tangled on propeller: Remove and clean propeller

Question 4

Parsun F20/F25 carburetor outboard: Engine will not start (starter operates)

Accepted Answer

Engine inner parts are damaged: Have serviced by your dealer
Engine stop switch lanyard is not attached: Attach lanyard
Fuel filter clogged: Clean or replace with recommended type
Fuel is contaminated or stale: Fill tank with clean, fresh fuel
Fuel pump has malfunctioned: Have serviced by your dealer
Fuel tank is empty: Fill tank with clean, fresh fuel
Ignition parts are faulty: Have serviced by your dealer
Ignition wiring damaged or poorly connected: Check wires for wear or breaks. Tighten all loose connections. Replace worn or broken wires
Spark plug cap(s) fitted incorrectly: Check and re-fit cap(s)
Spark plug(s) fouled or of incorrect type.: Inspect spark plug(s). Clean or replace with recommended type

Question 5

Parsun F20/F25 carburetor outboard: Starter will not operate

Accepted Answer

Shift level is not in neutral: Shift to neutral
Starter components are faulty: Have serviced by your dealer

Possible Reason	Recovery Action
Air vent screw on fuel tank is closed	Open air vent screw
Carburetor adjustments are incorrect	Have serviced by your dealer
Carburetor is clogged	Have serviced by your dealer
Choke knob is pulled out	Return to home position
Fuel filter clogged	Clean or replace with recommended type
Fuel is contaminated or stale	Fill tank with clean, fresh fuel
Fuel joint connection is incorrect	Connect correctly
Fuel pump is damaged	Have serviced by your dealer
Fuel system is obstructed	Check for pinched or kinked fuel line or other obstructions in fuel system
Ignition wiring damaged or poorly connected	Check wires for wear or breaks. Tighten all loose connections. Replace worn or broken wires
Motor angle is too high	Return to normal operating position
Spark plug gap is incorrect	Inspect and adjust as specified
Spark plug(s) fouled or of incorrect type.	Inspect spark plug(s). Clean or replace with recommended type
Specified engine oil is not being used	Check and replace oil as specified
Thermostat is faulty or clogged	Have serviced by your dealer
Throttle valve adjustment is incorrect	Have serviced by your dealer

Possible Reason	Recovery Action
Air vent screw on fuel tank is closed	Open air vent screw
Boat bottom is fouled with marine growth	Clean boat bottom
Fuel filter is clogged	Clean or replace with recommended type
Fuel is contaminated or stale	Fill tank with clean, fresh fuel
Fuel joint connection is incorrect	Connect correctly
Fuel pump has malfunctioned	Have serviced by your dealer
Fuel system is obstructed	Check for pinched or kinked fuel line or other obstructions in fuel system
Ignition parts have failed	Have serviced by your dealer
Ignition wiring is damaged or poorly connected	Check wires for wear or breaks. Tighten all loose connections. Replace worn or broken wires
Motor is mounted at incorrect transom height	Adjust motor to proper transom height
Propeller is damaged	Repair or replace propeller
Spark plug gap is incorrect	Inspect and adjust as specified
Spark plug(s) are fouled or incorrect type	Inspect spark plug(s). Clean or replace with recommended type
Specified engine oil is not being used	Check and replace oil as specified
Specified spark plug(s) are not being used	Check and replace spark plug(s) as specified
Thermostat is faulty or clogged	Have serviced by your dealer
Trim angle is incorrect	Adjust trim angle to achieve most efficient operation
Weeds or other foreign matter are tangled on gear housing	Remove foreign matter and clean lower unit

Possible Reason	Recovery Action
Motor mounting bolt is loose	Tighten bolt
Propeller is damaged	Repair or replace propeller
Propeller shaft is damaged	Have serviced by your dealer
Steering pivot is damaged	Have serviced by your dealer
Steering pivot is loose	Tighten it
Weeds or other foreign matter are tangled on propeller	Remove and clean propeller

Possible Reason	Recovery Action
Engine inner parts are damaged	Have serviced by your dealer
Engine stop switch lanyard is not attached	Attach lanyard
Fuel filter clogged	Clean or replace with recommended type
Fuel is contaminated or stale	Fill tank with clean, fresh fuel
Fuel pump has malfunctioned	Have serviced by your dealer
Fuel tank is empty	Fill tank with clean, fresh fuel
Ignition parts are faulty	Have serviced by your dealer
Ignition wiring damaged or poorly connected	Check wires for wear or breaks. Tighten all loose connections. Replace worn or broken wires
Spark plug cap(s) fitted incorrectly	Check and re-fit cap(s)
Spark plug(s) fouled or of incorrect type.	Inspect spark plug(s). Clean or replace with recommended type

Possible Reason	Recovery Action
Shift level is not in neutral	Shift to neutral
Starter components are faulty	Have serviced by your dealer

Parsun F20/F25 Spare Parts and Exploded Diagrams

Find Commonly Needed Parts

Water-pump and impeller parts

Carburetor parts

F20/F25 service shopping list and oil quantities

Select an Engine Assembly

Bottom cowling

BRACKET 1

BRACKET 2

BW BOTTOM COWLING

BW CYLINDER AND CRANKCASE

BW ELECTRIC

BW STARTER

CARBURETOR

CONTROL SYSTEM

CRANKSHAFT AND PISTON

CYLINDER AND CRANKCASE

ELECTRIC

FUEL

FUEL TANK 24L

FW BOTTOM COWLING AND BRACKET

FW CONTROL BOX

FW CYLINDER AND CRANKCASE

FW ELECTRIC

FW STARTER

INTAKE

LOWER CASING AND DRIVE 1

LOWER CASING AND DRIVE 2

OIL PAN

OIL PUMP

STARTER

STEERING

TOP COWLING

UPPER CASING

VALVE

Manuals