Yamaha F6CMHS Troubleshooting
| Engine Model: Yamaha F6CMHS |
| Engine Type: 4-stroke 1-cylinder short shaft gasoline outboard engine |
| Total Displacement: 8.5 cu.in (139 cc) |
| Rated Engine Power: 6 Hp (4.4 kW) at 5500 rpm |
| Fuel System: Carburetor |
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| Engine is not starting or hard starting |
Fuel tank is empty - Add fuel.
Incorrect fuel grade - Use quality fuel.
Air in fuel system - Bleed fuel system.
Spark plug wire is disconnected or loose - Check the spark plug wire connection, repair or replace.
Defective spark plug - Change spark plug as required.
Fuel filter is dirty - Change fuel filter.
Problems with carburetor adjustment - Adjust as required.
Dirty fuel lines - Fuel lines need to be cleaned.
Fuel tank air vent restricted or closed - Open or service air vent.
Fuel pump defective - Replace or repair fuel pump.
Throttle cable is adjusted improperly or worn - Change cable or adjust properly.
Valve clearance is improper - Adjust valve clearance.
Wrong valve timing - Set the valve timing correctly.
Spark plug is defective - Spark plug need to be replaced.
Dirty or defective carburetor - Replace or service carburetor.
Ignition coil is damaged - Change ignition coil as required.
Fuel tank air vent closed or restricted - Open or clean air vent.
Fuel pump is faulty - Repair or change fuel pump.
Choke system malfunction - Check and repair choke system.
Valve clearance is incorrect - Check and adjust.
Incorrect valve timing - Adjust valve timing as required.
Broken or bad valve springs - Replace valve springs.
Stuck valves - Clean the valves.
Ignition system is defective - Inspect ignition system and change failed components.
Fuel pump is faulty or clogged - Test fuel pump and replace if necessary.
Problems with carburetor adjustment - Adjust as required.
Fuel lines clogging - Service fuel lines.
Fuel tank air vent clogged or closed - Open or clean air vent.
Dirty fuel filter - Replace or clean fuel filter.
Damaged gaskets - Replace gaskets.
Dirty water intake screen - Clean and wash as required.
Choke system is damaged - Inspect and replace choke system components.
Engine is running overloaded - Reduce load.
Carburetor mixture is too lean - Set the carburetor properly.
Ignition timing is wrong - Ignition timing needs to be adjusted correctly.
Defective thermostat - Install new thermostat.
Faulty water pump - Change water pump as required.
Improper propeller diameter or pitch - Check the propeller size.
Damaged or improper size of propeller - Replace propeller.
Outboard engine is mounted too high or too low - Position the engine correctly.
Low engine oil level - Fill up the engine oil.
Oil pump failure - Change oil pump as required.
Water intake is blocked - Clean and wash as required.
Improper valve setting - Valves needs to be adjusted properly.
| Abnormal engine noise or knocking |
Low octane gasoline - Change gasoline.
Engine is overloaded - Load reducing required.
Low idle speed set incorrectly - Test and adjust.
Clogged or damaged fuel pump - Inspect fuel pump and change as required.
Crankshaft or main bearings failure - Repair or replace defective parts.
Piston rings or cylinder bore are worn - Replace faulty components.
Carburetor is improperly adjusted or clogged - Adjust the carburetor properly or clean it.
Fuel pump is defective or dirty - Check fuel pump and change if required.
Ignition system problems - Check ignition and replace faulty components.
Damaged cylinder head gasket - Cylinder-head gasket replacement required.
Worn powerhead components - Defective parts need to be replaced.
Stuck or burned valves - Replace or clean valves.
Improper propeller diameter or pitch - Install correct propeller.
Damaged or improper size of propeller - Replace propeller.
Outboard motor mounting height is set incorrectly - Adjust the engine to correct transom height.
Improper trim angle - Make the correct trim angle adjustment.
| Engine using too much gasoline |
Incorrect carburetor main jet adjustment - Adjust the carburetor main jet properly.
Defective or loose spark plug - Replace or tighten spark plug.
Piston, sleeve, or rings are damaged - Change faulty components.
| Engine vibrates excessively |
Damaged or improper size of propeller - Replace propeller.
Damaged propeller shaft - Replace propeller shaft.
Weeds in the propeller - Remove and clean propeller.
Motor mounting bolt is loose - Tighten the bolt as required.
Steering pivot is loose or damaged Tighten correctly or replace.
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| Outboard Engines Technical Specifications |
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