neighbor started his diesel
yesterday without opening the exhaust
valve. He said he heard what sounded like a backfire and the engine
quit. I helped him reattach the riser as it had come apart and we tightened several hose clamps on the exhaust
that were dripping. Then he tried to start it and it wouldn't start. At that point, dusk, I went home. I wonder what sort of damage he could have done.