Some of the problems with the Yanmar diesel engine include having a tight impeller/cover plate area, turbo washing and spinning of the fuel filter when it is over tightened. The engine may sometimes release large amounts of steam or run backwards for a couple of seconds.
The tight cover plate area requires loosening the clamps and bolts that hold the engine pump. The engine manual recommends using soapy water when washing the turbo blades; this product is not suitable for turbo washing. The Yanmar engine fires when one takes the finger off the start button too soon especially when the battery is too low.