What kind of oil
If you are using automobile engine oil, stop yesterday. Replace with Chevron delo 400 or Shell rotella diesel oil. I use Chevron 15-40 with great success. I change the oil every 50 hrs. or once a year. If you idle the engine long periods of time you will dilute the oil with unburned diesel which over time will wear out your bearings. Diesel, especially bio diesel are excellent solvents and will keep the inside of the engine clean but will cause high wear if diluted. Putting a little in an engine before over haul will make it easier to clean but can't be run under a load. You should run it hard for at least 10 minutes every time you operate it to bring it up to temp to get rid of any moisture/condensation in the oil to limit the oxidation of the oil, which causes corrosion. As a past mechanic, it kills me to see how so many abuse their engines and wonder why they have problems with so few hours on the engine.