Starter Will Not Turn Engine Over

This is a relatively common problem with Yanmar tractors and really any tractor and it can be a bit of a puzzle to solve. The key is just good old fashioned troubleshooting. If you just eliminate things it ISN'T wrong then you will be left with what is. 

Here is the order that I approach the problem the last few times my Yanmar didn't turn over.

I get on the tractor, hit the key expecting to hear the sweet clatter of the Yanmar diesel engine.... but nothing. Not even a click. 

The first thing I do it turn on the headlights and then try to start. If the headlights immediately go dim (not out) then I know I probably have a low battery and I just need to put it on the charger. If the headlights go completely out then I know I either have a really low battery or I have a bad connection. Usually at the battery terminals or where the ground wire attaches to the frame. I start by removing & cleaning all of the connections so they are bright shiny metal. You can also add a little grease to the connection to try to help keep them from corroding again. 

If the headlights stay bright then I know that the starter is not getting the signal to crank the engine. This can be from something simple like you forgot to depress the clutch fully and a safety switch is not being released or could be that a fuse is blown or the ignition switch has failed. 

You can start by using a volt meter on the small wire on the starter solenoid. The starter solenoid has 3 terminals. One has a big wire coming direct from the battery. One terminal has a very short section of big wire that disappears into the starter body, and one terminal is much smaller and has a single small wire attached to it. The small wire is the wire that tells the starter to engage. It should have zero volts with the key in the "off" and "run" position and 12v in the "start" position. If you don't get 12v there then you need to trace the wire back up to the ignition switch and see where the connection is lost. 

If you do get 12v there then the starter or solenoid could be bad or just stuck. You can try lightly tapping the starter with a hammer or block of wood. LIGHTLY is the key word. You are not trying to beat it into submission. 

If tapping does not work check out our next article on testing a starter coming soon!

 *If you are unsure that you have the skills to perform any of these steps please ask a mechanic for help.