Subaru EH12-2 Parts Manual

The recommended oil type for a Subaru EH12-2 engine is SAE 10W-30 for general use. In colder climates, SAE 5W-30 can be used for better performance.
The air filter should be checked every 50 hours of operation and replaced if necessary. Under dusty conditions, it may need cleaning or replacement more frequently.
The correct spark plug gap for a Subaru EH12-2 engine is 0.6-0.7 mm (0.024-0.028 inches).
Check the fuel level, ensure the spark plug is clean and properly gapped, verify that the air filter is not clogged, and ensure the ignition switch is in the correct position.
Start by turning the main mixture screw clockwise until lightly seated, then back out 1.5 turns. Adjust the idle mixture screw similarly. Fine-tune while the engine is running to achieve optimal performance.
Remove the spark plug and insert a compression gauge. Pull the starter rope several times to get a reading. A healthy engine should show a compression of around 120 psi.
Regular maintenance includes checking and changing the oil, inspecting and cleaning the air filter, checking the spark plug, and ensuring all bolts and screws are tight.
Check for loose mounting bolts, inspect the engine for damaged components, and ensure the crankshaft is not bent. Balancing rotating parts may also help reduce vibration.
Ensure the cooling fins are clean, check the oil level, and verify the engine is not operating under excessive load. Make sure the airflow around the engine is not obstructed.
To winterize, drain the fuel tank and carburetor, change the oil, remove the spark plug and add a tablespoon of oil into the cylinder, then pull the recoil starter to distribute the oil. Store the engine in a dry place.