Yamaha 25MLHG Owner's Manual
![Yamaha 25MLHG manual cover](/images/f1ac30b5f4adf5a09aa01151/thumbs/thumb175x175.webp)
To perform a basic maintenance check, ensure that the engine is off and cooled down. Check the fuel lines for cracks, inspect the propeller for damage, and verify that the water intake is clear of debris. Change the engine oil and replace the oil filter if necessary.
If the engine is not starting, first check the fuel level and ensure the fuel valve is open. Verify that the kill switch is not engaged and inspect the spark plugs for wear or damage. Clean or replace the spark plugs if needed.
Check the water pump impeller for wear and replace it if needed. Ensure that the water intake is not blocked by debris. Inspect the thermostat for proper operation and replace it if it is faulty.
Yamaha recommends using Yamalube 4M FC-W 10W-30 or 20W-40 engine oil for optimal performance of the 25MLHG. Ensure to use marine-grade oil for best results.
It is recommended to service your Yamaha 25MLHG every 100 hours of operation or at least once a year. Routine checks should include oil changes, fuel filter replacements, and inspection of the cooling system.
Excessive vibration can be caused by a damaged or unbalanced propeller. Inspect the propeller for any dents or bends and replace it if necessary. Also, check the engine mounts for wear and retighten or replace them as needed.
To winterize your engine, start by flushing it with fresh water to remove salt and debris. Drain the fuel system or add a fuel stabilizer to prevent fuel degradation. Change the engine oil and lubricate all moving parts. Store the engine in a dry, cool place.
To improve fuel efficiency, ensure that the propeller is correctly sized and not damaged. Regularly maintain the engine and use the recommended fuel-to-oil ratio. Avoid excessive idling and operate at optimal RPMs.
If the engine is running rough, check the fuel for contamination and replace it if necessary. Clean the carburetor and fuel lines. Inspect the spark plugs and replace them if they are fouled or worn.
To replace the spark plugs, first disconnect the spark plug wires. Use a spark plug socket to remove the old plugs. Check the gap on the new spark plugs and adjust if necessary. Install the new plugs and reconnect the wires securely.