Yes they run fine on veggie oil, especially free waste oil, from the local Japanese restaurant (soy is best). The room just smells like french fries. The trick is a two way supply line. You run for 10 minutes on straight diesel and when warm you switch over with no loss of power. There are many other options and I have mixed in engine oil, peanut oil (Rudolph Diesels original favorite fuel when he invented the engine
) and other things. Ah but that is another thread for another time.