Onan 5500 Backfires and Dies under a load
Good Morning.. Im hoping to find the Onan guru's that are here... For the past year I have been searching for answers and replacing parts with no improvement. I have an Onan 5500 with less than 100...
Forum Discussion
"I assume from the backfiring?"
I can't see it or hear it run online. That said:
Backfiring implies that unburned mixture IN THE INTAKE tract is being ignited and burned. (not the exhaust) Can you confirm that? Backfiring is a classic condition of a lean mixture which would point to a vacuum leak somewhere in the intake. Are all the breather hoses connected properly? Is the (new) carburetor properly seated on the manifold with all the gaskets? When hot, a lean mixture can lead to pre-ignition/detonation which may sound like a backfire.
What happens if you manually force the choke on with the engine warmed up, loaded, and backfiring? (richen the mixture) Any improvement?
Do you have a compression tester? If so, does the engine meet the compression specs?
Chum lee
I can't see it or hear it run online. That said:
Backfiring implies that unburned mixture IN THE INTAKE tract is being ignited and burned. (not the exhaust) Can you confirm that? Backfiring is a classic condition of a lean mixture which would point to a vacuum leak somewhere in the intake. Are all the breather hoses connected properly? Is the (new) carburetor properly seated on the manifold with all the gaskets? When hot, a lean mixture can lead to pre-ignition/detonation which may sound like a backfire.
What happens if you manually force the choke on with the engine warmed up, loaded, and backfiring? (richen the mixture) Any improvement?
Do you have a compression tester? If so, does the engine meet the compression specs?
Chum lee
