Yamaha 25ESH Troubleshooting
| Engine Model: Yamaha 25ESH |
| Engine Type: 2-stroke 2-cylinder short shaft gasoline outboard engine |
| Total Displacement: 24.1 cu.in (395 cc) |
| Rated Engine Power: 25 Hp (18.4 kW) at 6000 rpm |
| Fuel System: Carburetor |
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| Engine difficult to start or won't start |
Empty fuel tank - Add fuel.
Wrong grade of gasoline - Change fuel.
Dirty fuel system - Check and clean.
Disconnected or loose spark plug wire - Inspect the spark plug wire connection, replace or repair.
Faulty spark plug - Install new spark plug.
Plugged fuel filter - Fuel filter needs changing.
Carburetor malfunction - Check and repair as required.
Restricted fuel lines - Service fuel lines.
Closed or restricted fuel tank air vent - Open or clean air vent.
Lack of fuel pump pressure - Change or rebuild fuel pump.
Worn or faulty reed valve - Replace reed valve as required.
| Engine starts but stalls suddenly |
Spark plug is defective - Change spark plug as required.
Carburetor is dirty or defective - Service or replace carburetor.
Ignition coil is not working - Install a new ignition coil.
Fuel tank air vent closed or restricted - Open or clean air vent.
Low fuel pump pressure - Replace or rebuild fuel pump.
Ignition system problems - Test ignition and replace failed parts.
Dirty or faulty fuel pump - Clean or install new fuel pump.
Carburetor not adjusted - Adjust according to instructions.
Fuel lines clogging - Clean fuel system lines.
Closed or clogged fuel tank air vent - Open or clean air vent.
Plugged fuel filter - Replace or clean fuel filter.
Worn gaskets - Replace gaskets.
Engine overloaded - Reduce the load.
Carburetor is running lean - Adjust carburetor properly.
Wrong ignition timing - Adjust ignition timing correctly.
Damaged thermostat - Thermostat need to be replaced.
Faulty water pump - Install new water pump.
Incorrect propeller selection - Install correct propeller.
Damaged or improper size of propeller - Replace propeller.
Outboard engine is positioned too low or too high - Position the engine correctly.
Stale gasoline - Use correct gasoline.
Engine overloaded - Reduce the load.
Low idle speed setting is incorrect - Correct idle adjustment.
Dirty or damaged fuel pump - Inspect fuel pump and change as required.
Crankshaft or main bearings are worn out - Worn parts replacement required.
Worn piston rings or cylinder bore - Replace faulty components.
Incorrectly adjusted or dirty carburetor - Clean or correctly adjust carburetor.
Fuel pump is defective or dirty - Clean or change fuel pump.
Ignition system problems - Check ignition and replace faulty components.
Worn gaskets - Replace gaskets.
Damaged powerhead parts - Replace defective parts.
Incorrect propeller selection - Install correct propeller.
Damaged or improper size of propeller - Replace propeller.
Outboard engine mounting height improperly - Have motor adjusted to proper transom height.
Trim angle is incorrect - Adjust trim angle correctly.
Carburetor main jet is incorrectly adjusted - Adjust the carburetor main jet properly.
Loose or defective spark plug - Re-tighten or change the spark plug.
Worn sleeve, piston, or rings - Change defective parts.
| Excessive motor vibration |
Damaged or improper size of propeller - Replace propeller.
Damaged propeller shaft - Have propeller shaft replaced.
Weeds clogs the propeller - Clean the propeller.
Engine mounting bolt is not tightened - Tighten bolt.
Steering pivot is faulty or loose Tighten correctly or replace.
Low battery capacity - Battery is drained, recharge it.
Battery does not hold charge - Battery needs to be serviced or replaced.
Disconnected cables or faulty battery terminals - Connect wiring correctly or install new terminals.
Starter motor failure - Starter should be changed.
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| Outboard Engines Technical Specifications |
| Small Engines Technical Specifications |
| Car Engines Technical Specifications |
| Industrial Engines Technical Specifications |
