Onan 5.5HGJAB-1038C
Hi all, I am new here. I have an Onan HGJAB-1038C Spec C generator that is surging while under a load from the A/C. It will do this for a minute or two then die. I just replaced the carb and campi...
Forum Discussion
I have used Facet pumps but I think they about 4 to 6 psi. I would try to find out what the specs of your oem pump are. If the pressure is too high it may flood or run rich. It's been too long to remember all this stuff but I think some run at 3 psi or so?
There are 3 areas that could cause this. Fuel, Vacuum and governor/linkage issues.
You eliminated the orifices in the carb as a restriction. You eliminated the fuel lines and the tank. You didn't 100 % prove that it isn't fuel supply though. But on the other hand the pump "should" be able to do that and at the same time you have done a preventive repair. I have seen these pumps not last long and also seen them very old and seen cars that go 40,000 or 200,000.
So as far as vacuum, have you tried to manually slow the engine with the throttle linkage? If so was it able to stay running? Maybe not at idle but maybe close to idle?
An engine that runs at a constant speed and has a vacuum leak can start because the choke can provide a rich enough mixture. The vac leak could show up under load because it would lean the air/fuel mixture. A throttled engine could show signs at all speeds with idle being worse.
The manifold isnt loose is it? In fact I think Ive fixed onans used on lawn equipment that had loose intake manifolds.
There are 3 areas that could cause this. Fuel, Vacuum and governor/linkage issues.
You eliminated the orifices in the carb as a restriction. You eliminated the fuel lines and the tank. You didn't 100 % prove that it isn't fuel supply though. But on the other hand the pump "should" be able to do that and at the same time you have done a preventive repair. I have seen these pumps not last long and also seen them very old and seen cars that go 40,000 or 200,000.
So as far as vacuum, have you tried to manually slow the engine with the throttle linkage? If so was it able to stay running? Maybe not at idle but maybe close to idle?
An engine that runs at a constant speed and has a vacuum leak can start because the choke can provide a rich enough mixture. The vac leak could show up under load because it would lean the air/fuel mixture. A throttled engine could show signs at all speeds with idle being worse.
The manifold isnt loose is it? In fact I think Ive fixed onans used on lawn equipment that had loose intake manifolds.
