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Onan 7500 Quiet Diesel - "gallops" when trying to start

tkcas01
Explorer
Explorer
When my gen is cold, it starts normally. However, if I try to start it when it is hot, it "gallops", meaning it sounds like it is wanting to start but not quite kicking in, and it jumps somewhat violently. Any thoughts on what this might be a symptom of? It seems like the fuel is igniting too early - maybe as the result of the hot cylinders? I recently replaced the air and fuel filters and that did no good.
Roaming Full Timer
2 REPLIES 2

eHoefler
Explorer II
Explorer II
Normal. It is called " Dieseling". The simple design of the engine is like the old ones unlike today's diesels. It is from incomplete combustion of a cold engine, as the engine starts to warm up, it will burn the fuel more efficiently.
2021 Ram Limited, 3500, Crew Cab, 1075FTPD of Torque!, Max Tow, Long bed, 4 x 4, Dually,
2006 40' Landmark Mt. Rushmore

nevadanick
Explorer
Explorer
Sounds to me like it isnt getting fuel, possibly a check valve that when warm lets the fuel bleed off. If it has a primer try priming before you start it when hot and see if that makes it bettter. If so then fuel is bleeding off.