Generator Clacking

wildmanbaker wrote:
Holstein, We have an 03, 5.5 Onan. In the summer, we regularly run it with the windows open, and can barley here it running. I started ours and let it warm up, then shut it off, disconnected the fuel supply line and plugged the tank supply and covered the inlet to the fuel filter, then started the gen. As soon as the generator started, I could not hear the fuel pump, even though it was running dry. The loudest part of the generator, when it is running is the cooling air flow.

Are you running the gen with the access door in place? If not it will overheat. Next, check the bottom for a cover that starts at the back and comes within about 2" of the oil filter. Under the bottom air shield should be perforated screen that keeps debris out of the air flow. It is designed to get outside turbulent air for cooling, not from under the MH. When you are actually running on the road and any speed faster than I can run, the hot air from the engine, will exit from behind the transmission, not out the sides. If all the panels are in place, if is very unlikely that it is overheating from the engine source. The fuel pump should be mounted to the large cast base of the generator, so very little noise should be transmitted from it. I assume that you are using 87 fuel? It does seem that you may have a fuel problem. Does it give problems with a full tank, the same as a 1/2 tank of fuel?

To tell you the truth, we have never traveled with the generator running, as the dash AC does a good job of cooling the entire MH, even when it is 106 out.

I get the clacking noise even when the generator and motorhome aren't running. The noise is coming from the fuel pump, not the engine. So when I prime the engine, I get the clacking noise. Even once the generator starts, I can still hear the loud clacking noise.

I like your suggestion to put a thermometer down there. I've got one on the opposite side at the propane tank and it hit 120 - 130 when I was having problems with the generator so I know it's hot on at least one side. I'm assuming it's even hotter on the generator side because it gets the engine heat plus the generator heat. The problem occurs at any fuel tank level, but only when things heat up.

BTW, I only run the generator with the access door closed. Usually, if I'm stopped, I'm at a full hookup campsite so I'm not running the generator while camped. My dash A/C is pretty weak and with kids in the back, It's totally inadequate.