OK, so my 5KW, BGM gen is broken too. 72 hours use total.
It will crank strong, but not run. Would sometimes start and run, but eventually die like switched off. Governor arm on top of gen no longer moves on cranking.
Controller brd=OK (per flightsystems)
Oil pressure switch=OK
Gasoline level in tank=FULL
Air filter=like new
Spark plugs=like new
All carb linkages=working
All neg grounds=tight
All other electrical connections I can find=tight
i see no spark from front plug, quick start sprayed into carb has no effect. So I suspect problem is electric.
If nothing above points to "The Problem" I am going to attempt to follow the trouble-shooting flow chart in the back of the Onan service manual. Taking a systematic approach! Finally.....
But the first step requires taking a read on the gen's voltage on the "input side of the breakers". Where is the easiest/best place to find that, since the breakers are housed inside the body of the gen?
thank you for the help! This has been a real time waster, but educational and manly.
Mark, Jean, Paul & Lizzy (the mutt)
1997 Fleetwood Southwind Storm 34LS
Thirsty, noisy & clunky. She ain't pretty, but she sure is fun! "Aerodynamics are for people who can't build engines." Enzo Ferrari
The fact that is does run occasionally, leads me to think that the fuel is in question. Have you tried running something like SeaFoam in the fuel....or have the carburator replaced?
When you say that the fuel filter is OK, does that mean you replace it, or you figure it's OK, since it's got so few hours?
How did you test the fuel pump? Can you hear it "prime"? Does it do the same thing (make the priming sound) when the engine dies..and you try and prime again? It could be (as was the case with our 4Kw) that the pump was bad, and would overheat and trip off after about 10 minutes. If I left the generator alone for a few minutes, it would start up again, but then stall.
I found that troubleshooting step in the manual, so you are headed in the right direction.
Sorry, can't help much with the location of breakers on your unit, as it's different than what I have, but there is bound to be someone on here with experience.
It would also be good, if you posted the Model number and S/N, as there are a few Onan Techs who could really help you, but they always want that information to make sure they are writing about the correct unit.
And a last note....the number of hours on that genset are minimal at best. You should have about 3 times that many hours, if you were just putting an hour/month to exercise it. Which is another reason that I keep thinking the fuel in the carb jets has caked up on it....
Bill & Claudia / DD Jenn / DS Chris / GS MJ Dogs: Sophie, Abby, Brandy, Kahlie, Annie, Maggie, Tugger & Beau RIP: Cookie, Foxy & Gidget @ Rainbow Bridge.
2000 Winnebago "Minnie" 31C, Ford V-10
Purchased April 2008 FMCA# F407293 The Pets
If your genset is a '97 it's probably pretty close in style to mine. I found following the FlightSystems trouble shooting guide (PDF) from their web site really helped debug my problems. The Onan guide wasn't much help. Part of the debug using the FlightSystems PDF gives you resistance values that are pretty easy to measure and if out of range, they give you definite causes.
One thing you didn't mention is whether or not you cleaned the slip rings. They must really be dirty at that age with only 72 hours on it.
It also sounds like you have more then one problem.
The spark issue I had was a simple poor connection at the spark plug connector. Had to strip the insulation back 1/2" to find good wire. Then the slip ring measurement was too high so I had to sand it, and the Voltage Regulator (different then the control board) was bad.
Many users have posted that their fuel hose developed leaks up on top of the fuel tank. Test is to clamp it off and remove it from the fuel pump input and connect a hose from there to a gas can.
Weird, how is the coil? No spark start from the spark plug and work your way back.
4 whopping cylinders on Toyota RV's. Talk about great getting good MPG. Also I have a very light foot on the pedal. I followed some MPG advice on Livingpress.com and I now get 22 MPG! Not bad for a home on wheels.
My 5.5 ONAN had a problem last month - would run for a minute or so if I primed it but then stop - sometimes run for 20 seconds - sometimes run for a minute - ERROR Code was either 36 or 37.
Took it to the shop - ONAN TECH CLEANED THE CARB AND VOILA - PROBLEM SOLVED.
thanks for the quick replies!
SLip rings: Forgot to mention I did buy the little slip ring erasers and cleaned the contacts. they weren't too bad actually.
Fuel filter: replaced by previous owner. Probably pristine inside. fuel runs straight through.
Fuel pump: removed line at carb. cranked gen and clean fuel spurted out. About 2 "spurts" per second at idle.
Fuel pump prime? my pump does nothing. My gen has no label on either switch for priming. SHould it prime? I have held both switches down on the "stop" side for 1 minute + with no clicking of any kind. No change at carb, gen etc.
Let me go try pouring some raw fuel in the carb. But if the electrics aren't responding, I don't think it can do any good. But I'm exasperated.
I have the flight systems guide. I'll try that prior to the Onan if I don't burn the house down.
I will let you know.
My 5500 onan has 158 hours, last week it would start, run a rough for a few min and die. I changed the air filter and it has run perfect. the air filter was plugged with only 158 hours. the generator is hung under the back end on mine, so I bought a spare filter to keep in coach. Manual states to change at 400 hr, not on mine. the location picks up a lot of dust from road. try to run it without the air filter in the drive way. If it starts, it will take a few mins for the plugs to burn off and run right.
I have a schematic of the Onan 'Control Board' and they are pretty simple. Just some steering diodes, 3 relays, switch, fuse, and 2-3 resistors. First time I had to work on my genset (too long ago to remember with the problem was), I found a corrosion short across two terminals of a connector on the board. Next time it was a corrosion caused OPEN. One connector lead had corroded away so my remote start wouldn't work. And that's on a board that's conformal coated!
So, recommend you remove the control board and clean it with contact spray just for PM.
Thank you for the suggestions. I've messed-around with my old doubler meter, but have never learned enough about electrical systems to have much confidence in my abilities or the test results.
Control Bd: The boards are pretty simple. I cleaned the control bd with electrical cleaner before sending it to flight systems. I saw no corrosion on the component leads or connectors. This RV came from Florida and is now living in Alabama. So corrosion is hard to find on anything but the exhaust manifold and muffler.
Air cleaner: I tried several times to start the gen without the air cleaner. That trick used to work with my dad's old lawnmowers. not on this unfortunately.
GAs starvation: I manually opened the choke and shot a healthy dose of Quick Start into the carb. Nothing good happened. So sparks are what are missing. The carb is possibly gooped, but should start.
I couldn't find my copy of the flight systems trouble-shooting list, so i used Onan's. I couldn't get any AC voltage off the circuit breakers. they were easy to get to, but I'm pretty sure I didn't hook-up the test leads to the circuit breakers right.
Question: how should I check the input side of the two breakers? + input and ground? Or is each magnetic breaker a different polarity? + and -?
I did get DC voltage off the brushes, but don't understand the readings. When cranking the gen the meter's needle would hover in the 9-12volt range for 2-3 seconds, but would then go off the far end of the range. I repeated the test a couple of times with leads swapped. Same result. What's up with that? I used one lead on each brush + and -. Is that the way the voltage is flowing in there?
I'm too determined to give up. I can't stand the thought of owning this gen and not using it. I can't afford to pay out the rear for a fix and I WANT TO BEAT THE DARN THING!!!
Remember that the voltage on the input side of the breakers is AC. So your meter should be set for AC not DC. You mention +/- and with AC it doesn't matter, that's why I'm mentioning it, but how you set your meter does matter.
The voltage on the brushes would get what's called 'Flash' voltage from the control board for 2-3 seconds while the genset starts, then the Voltage Regulator takes over and adjusts that voltage up/down to maintain 120Vac at the output. It does this rapidly in some cases if there are varying loads on the AC. What you are probably reading is either a bad Voltage Regulator output, or an attempt by the VR to compensate for something as simple as a minor short from hot to ground in the wiring. There is also the possibility that your Transfer Switch coil is shorted internally.
BTW, those breakers are NOT magnetic...they are just like the AC breakers in your house and operate (open circuit) when the load is to high, ie, drawing to much current.