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Troubleshooting Your Yanmar Tractor Engine

Yanmar diesel tractor engines need Air, Fuel, and Compression to run.

Here are four troubleshooting tips to follow if you find that your Yanmar heavy-duty engine will not start OR starts and dies.

Tip #1: Inspect Air Cleaner

You must inspect your air cleaner to make sure it is free of debris.

Mice tend to build nests in the intake. Then they get sucked into the filter when you try to start the engine.

Simply remove the filter cover. Check for debris. Look for tiny mice with windblown fur that could be plugging the filter.

You should also remove the muffler. Air needs to get into the engine and it also needs to get out. In many instances, the internal baffles of the mufflers have fallen apart and blocked the exhaust. This could keep your engine from starting.

Tip #2: Test Fuel Injectors

You do not need to remove them completely. Simply loosen them several turns. Then, crank over the engine. Make sure the throttle is in the “run” or “full” throttle position. Look for small squirts of fuel coming out of each of the lines. You are not looking for a lot of fuel; roughly a ½ teaspoon.

An alternate way to test your injectors is by removing them from the engine. Then hook them back up to the steel fuel lines. Crank the engine over at full throttle. Let the injectors spray onto a piece of cardboard.