I have an Onan 4KY generator in my Class C. I have exercised it each month per the owner's manual. Today I was going to do the monthly exercise for 2 hours. I tried to start it up twice, it spun over, but would not start. On the third try, all it would do was click and hum, but not turn over. The battery is almost new and has been on a maintainer, and the connections to the battery were tight. I got a code 32 and checked the oil etc. Oil level was midway on the dipstick. I read somewhere else that the starter might be stuck, so I tried to turn the flywheel to free it up. The flywheel would not move by hand. I have run out of daylight, but does anyone have any more suggestions before I tackle it again tomorrow. Very frustrating.

u need to pull plug to spin by hand

Hmmm..well i hate to say it, but if you were cranking the starter for a long time, it may have burnt out. Hopefully you just wore the battery down, as could happen if you had trouble getting it fire up.The first thing I would do is to charge the battery up again, and give it another try, to see if the starter will spin. If still no go, it could be the starter solenoid/relay, rather than the starter itself. They can overheat as well and burn out.Is the fuel quite old, and not had any fuel stabilizer added to it? Could be the reason it wasn't starting for you. Old fuel can get pretty gummy after just 6 months, and plug up carb jets, etc. If you do get it to spin again, you could try a shot of "cold start" in the air intake. Sometimes this will allow the engine to fire up long enough, to suck through any gum or varnish. Don't get carried away with the cold start though, as to much can harm an engine.

u need to pull plug to spin by handalso see u in NE Ga how cold is it thick oil?

Sfla2 wrote:u need to pull plug to spin by handalso see u in NE Ga how cold is it thick oil?OK this is the kind of info I was looking for. First, I will recharge the battery, while that is happening I will pull the plug and try to spin the flywheel to make sure the starter is not stuck. As for the temp, it was down to 20 degrees last nite. I need to check my manual to see what oil I put in it, I'm thinking it was 10W-30. I don't think I overheated the starter, but I guess I will find out soon enough. Thanks and I will keep you posted in case someone else has this problem.

We had another case that sounds like yours a week or two ago. The battery was a little low. I forget if the batt had to be taken someplace to be charged then brought back, or charged in place. I mention that because the take-out-to-charge route probably would also result in terminals checked and cleaned. Did you remember to "prime" the carb with fuel by holding the rocker switch to OFF before cranking? I end up doing ours at least twice, even in our warmer weather. You won't flood it doing that, provided the carb's Float Needle and Seat are OK. You'll just know the gas is right there, and hopefully reduce cranking time.

Onan generator problem | Good Sam Community

14 Replies

kcny
Explorer
Jan 06, 2014
Thanks Bruce, I don't recall hearing the pump. In the spring when I get the MH out of storage, I'll have my wife try the prime on the switch inside while I stand by the generator and listen.

j-d: I had the "piston position" issue happen on my MQ 4k. Now I always carry a 9/16" socket and a small breaker bar with me! Those things do flop around when holding stop, sounds like it is gonna fall through the bay floor.
j-d
Explorer II
Jan 06, 2014
Glad it's running, Dennis.

I don't know if an MQ can do this, but sometimes an engine will stop with its piston exactly at Top- or Bottom-Dead-Center. When that happens, the "Starter" (whether a starter motor or you and me pulling on a cord) gets very little leverage against the piston.

The way the MQ engine flops around when we're holding the STOP button, who knows where it lands?

I started ours today, and as usual, it started the same way Bruce's does. Prime, Try, Prime, Try (maybe one more Prime, Try) and it starts. Ours is from 2002, 420 hours, new carburetor and logic board, original fuel pump.
BruceMc
Explorer III
Jan 06, 2014
The pump is located within the generator housing, just behind the logic module.
When you press and hold the off button, nothing happens for about 4 seconds, then the prime process starts. The indicator light illuminates (in mine, anyway) and the pump runs as long as the switch is held in the off position.
kcny
Explorer
Jan 06, 2014
Bruce - curious, is the pump part of the generator or is it external (like added near the MH fuel tank for example). I don't recall hearing my fuel pump making a noise when holding the switch, so I wonder if it is even working!
BruceMc
Explorer III
Jan 05, 2014
Good to hear you got it going. I have to prime our 4K every time or it just sets there and cranks. Even when I prime it, it still takes a couple cycles of prime/crank to get it going. I've learned not to crank more than 3-5 seconds, if it hasn't fired by then, it's not going to.

I installed a new fuel pump & filter late last summer as the fuel pump quit. The start behavior is the same. I had the bright idea that it was hard to start due to the failing pump, but it's still hard to start unless it has had a proper prime.

There is a marked difference in the sound of the fuel pump during the prime process, I'll hold the prime button until the pump starts to quiet down then try starting it.
dennislanier
Explorer
Jan 04, 2014
Ok guys, thanks for the input. I got the problem fixed (at least temporarily). Turns out it was a "stuck" starter/bendix. With a good bit of difficulty I got a 9/16 socket and ratchet on the flywheel and really had to strain, but moved it an inch or so which was enough to break it loose. After that, it turned over just fine and fired up. Although my owners manual says to only prime it when it has run out of fuel I am going to prime it next time I try to start it cold and see if it starts better. It is supposed to get really cold next week so I wanted to have some backup if the power goes out. Thanks again and hopefully this will help someone in the future.
gotsmart
Explorer
Jan 04, 2014
dennislanier wrote:
I went back and re-checked the previous information I had found and it did not say anything about removing the spark plug. Do you think it was just omitted by mistake or should you be able to move it with a ratchet without taking the plug out?

Just checking to see if you missed j-d saying to prime the generator before starting it. With my Onan MQ 4K the start button on the test panel is a 2 position rocker switch. I press and hold the bottom of the switch in for 20-30 seconds to prime it. I release it, then I press and hold the top of the switch to start it. Your setup may be different, but without first priming the genset it could take a very long time for it to start.
Davidlatham2012
Explorer
Jan 04, 2014
Your motor is fine. Does your generator start off cranking batteries or house batteries?
dennislanier
Explorer
Jan 04, 2014
I went back and re-checked the previous information I had found and it did not say anything about removing the spark plug. Do you think it was just omitted by mistake or should you be able to move it with a ratchet without taking the plug out?
j-d
Explorer II
Jan 04, 2014
We had another case that sounds like yours a week or two ago. The battery was a little low. I forget if the batt had to be taken someplace to be charged then brought back, or charged in place. I mention that because the take-out-to-charge route probably would also result in terminals checked and cleaned. Did you remember to "prime" the carb with fuel by holding the rocker switch to OFF before cranking? I end up doing ours at least twice, even in our warmer weather. You won't flood it doing that, provided the carb's Float Needle and Seat are OK. You'll just know the gas is right there, and hopefully reduce cranking time.

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Onan generator problem

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