The Kubota diesel engine has such a simple and rugged set-up that there are very few parts or functions that are likely to fail. However, if for some reason your Kubota cannot start, you can take several steps to troubleshoot your engine before sending it to a professional.
Check the Fuses
Start the troubleshooting process by checking the fuse block. Make sure all the fuses have been inserted properly into the main block. If the connections check out, the next step is to see if all the fuses are functional and whether they have the correct amperages.
If your engine does not have a fuse issue, it is time to check the battery. If you have a sealed battery, try to jump start it. If the battery requires water, open the cap, and see if there is water left. If the battery is dry, add water, and try to start the engine.
If the engine doesn't turn over, locate the starter, which is near the radiator on the left or right side, depending on the model of your Kubota engine. If the starter does not crank the motor over, gently tap the starter housing with a hammer. Be extra careful not to damage the starter or any of the surrounding components.
Checking the Fuel
If the starter is cranking but you are not getting any signs of life from the engine, you might want to make sure you have the correct fuel in your tractor. Diesel engines will run on a lot of different fuels, but it is a surprisingly common mistake for someone to put gasoline in the tank instead of diesel fuel. That error can be catastrophic for the motor. If there is gasoline in the tank, you need to drain the tank and flush the fuel system completely and as soon as possible. If you have diesel in the tank, you must check to see if there is any sign that the fuel is reaching the cylinders. The easiest way to do this is to look for grey, blue or black smoke in your exhaust. Any of these colours indicates that fuel is reaching the diesel combustion chambers. White smoke indicates that the fuel is burning but not combusting. If you have dark smoke but the engine still won't run, try bleeding the fuel system until you have pure diesel fuel flowing out of the bleeder spout.
If none of these troubleshooting steps work, your Kubota engine probably needs a compression test. That test is best left to the Kubota dealer or a local diesel mechanic. If, in fact, there is a compression problem, the engine more than likely will need to be engine totally rebuilt, or, even worse, you will have to drop in a whole new engine.