Yamaha 15 FMHS Troubleshooting
| Engine Model: Yamaha 15 FMHS |
| Engine Type: 2-stroke 2-cylinder short shaft gasoline outboard engine |
| Total Displacement: 15 cu.in (246 cc) |
| Rated Engine Power: 15 Hp (11 kW) at 5500 rpm |
| Fuel System: Carburetor |
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| Engine hard to start or won't start |
No gasoline in tank - Fill gasoline up.
Low-quality gasoline - Use correct fuel grade.
Fuel system clogged - Repair or replace.
Defective wiring connection of spark plug - Inspect the spark plug wire connection, replace or repair.
Spark plug is faulty - Change spark plug as required.
Fuel filter is plugged - Install new filter.
Carburetor malfunction - Check and repair as required.
Fuel lines are dirty - Fuel lines must be clean.
Fuel tank air vent clogged or closed - Open or clean air vent.
Fuel pump pressure is low - Change or rebuild fuel pump.
Reed valve is worn or damaged - Install new reed valve.
| Engine starts but then shuts off |
Faulty spark plug - Spark plug need to be replaced.
Dirty or faulty carburetor - Service or change carburetor.
Ignition coil is defective - Replace ignition coil as necessary.
Fuel tank air vent closed or restricted - Fuel tank air vent need to be opened or cleaned.
Low fuel pump pressure - Change or rebuild fuel pump.
Defective ignition system - Check ignition and replace faulty components.
Dirty or damaged fuel pump - Check fuel pump and replace if necessary.
Carburetor malfunction - Check and repair as required.
Fuel lines are dirty - Fuel lines must be clean.
Closed or restricted fuel tank air vent - Open or service air vent.
Dirty fuel filter - Fuel filter needs to be replaced.
Damaged gaskets - Install new gaskets.
Engine is under excessive load - Load reducing required.
Carburetor mixture is too lean - Adjust carburetor properly.
Ignition timing is incorrect - Adjust ignition timing as required.
Thermostat is faulty - Replace thermostat.
Damaged water pump - Water pump need to be replaced.
Propeller pitch or diameter incorrect - Check the propeller size.
Damaged or bent propeller - Have propeller repaired or replaced.
Outboard motor is positioned too low or too high - Mount the motor as required.
Low octane fuel - Change gasoline.
Engine overloaded - Load reducing required.
Incorrect low idle setting - Adjustment required.
Clogged or defective fuel pump - Service or replace fuel pump.
Main bearings or crankshaft failure - Have bearings or crankshaft replaced.
Worn cylinder bore or piston rings - Replace faulty parts.
Improperly or clogged carburetor - Service or correctly adjust carburetor.
Clogged or damaged fuel pump - Inspect fuel pump and change as required.
Ignition system problems - Inspect ignition system and change failed components.
Worn gaskets - Replace gaskets.
Damaged powerhead parts - Defective parts need to be replaced.
Improper propeller diameter or pitch - Check the propeller size.
Damaged or bent propeller - Replace propeller.
Incorrect outboard motor mounting height - Check the outboard engine mounting height.
Trim angle is incorrect - Adjust trim angle.
Carburetor main jet is improperly adjusted - Adjust it correctly.
Spark plug is loose or faulty - Change or re-tighten spark plug.
Worn rings, piston, or sleeve - Replace faulty components.
| Engine vibrates excessively |
Propeller bent or damaged - Replace propeller.
Propeller shaft damaged - Propeller shaft needs to be replaced.
Weeds wraped around propeller - Remove weeds from propeller.
Engine mounting bolt is not tightened - Tighten bolt.
Damaged or loose steering pivot Tighten or replace.
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| Outboard Engines Technical Specifications |
| Small Engines Technical Specifications |
| Car Engines Technical Specifications |
| Industrial Engines Technical Specifications |
