Check the fuel tank to ensure you aren’t out of fuel and ensure you’re using the proper starting procedure for your specific John Deere product if the engine cranks but won’t start.
Check the exhaust to ensure it isn’t plugged or obstructed, and replace your fuel filter with an authorized John Deere filter if it’s plugged and you have trouble starting the engine.
Add oil to the crankcase of your John Deere diesel engine if it makes a knocking sound while in use or if the oil level on the gauge says it's low. Add oil that is of the same viscosity as recommended in your owner’s manual.
Reduce the load on the engine and operate the machinery with less resistance if the engine shows a lack of power. Inspect and replace the air cleaner if it is clogged or dirty.
Look for leaks in the gaskets, drain plug and oil lines if the engine is using oil at a high rate.
Ensure the fuel you are using is diesel and allow the engine to warm up for a few minutes prior to use if white smoke comes from the exhaust when you start the engine.