Yanmar Trouble Shooting Tips
Won't Start Or Starts Then Dies
Note: There are a few Yanmar tractors including most of the "F" series and a few of the '20 series that have an electric fuel shutoff (turning the key to the off position kills the engine instead of having to pull a cable). This electric shutoff will need to be diagnosed separately to be sure it is working.
These little Yanmar diesel engines are very simple. They only need 3 things to run: Fuel, Spark (in the form of compression), and Air. The following is arranged from easiest to check to most difficult to check.
You can also test your injectors by removing them from the engine and hooking them back up to the steel fuel lines. Crank the engine over at full throttle and let them spray onto a piece of cardboard. ** DANGER! The fuel sprays at a super high pressure. It will easily cut right through your skin & inject you with diesel (FYI... That is bad). You are looking for a nice even cone mist (not a squirt or stream or drips).
If yes, then fuel is not likely your problem.
Check to be sure you are getting a good steady stream of fuel going into the injection pump. The easiest way to test this is to disconnect the fuel hose where it attaches to the injection pump. You want to be sure that you have a good flow of fuel and be sure that it does not taper off after a few seconds. It is best to let the fuel run out of the hose long enough to fill a quart bottle just to be sure you are not getting a 'gush' of fuel which then turns to a dribble after a few seconds.
Work your way up stream inspecting everything all the way up until you end up at the fuel tank. You will eventually find a place where there is a steady flow of fuel on one side of an item or hose and not on the other. Fuel going into a filter but not out, for example. Once you find that then you have found your problem.
This is a basic troubleshooting list. Of course, there are other problems that are less like to happen but can occur. It was impossible to include all of the possible problems in this article but the things listed above account for over 90% of our tech support calls. If you do not feel like you have the ability to do these test then please contact a local mechanic or give us a call. As with pretty much anything in life... there is the risk of injury doing some of these tests.