Generator Repair

[Skillet]

When I picked up my Chinook last March, the generator never really ran right. Eventually, after a few months, it would just turn over and do nothing but throw the "36" code. I have a Cummins/Onan dealer/repair shop just a few miles away and left it with them. They found the ignition coil was broken. Fixed and I was on my way.
This past October I was at Ocracoke Island and the generator started doing the hit and miss again. Finally in mid-December it would just turn and give the "36" code again. I made arrangements for Cummins to look at it after New Year's and got it in last week. The tech couldn't find the source and verified the fuel was coming through the line just fine, air filter good, etc. He said he would have to check the frequency and wanted to drop the generator. I was told that as he was about to start dropping it he found that the bolt that holds the grounding wire (or strap-can't remember) had backed out and all he had to do was replace it and it worked like it should. I got it back and it hums along better than before. I'm guessing that because it was loose, that was why I was getting intermittent work out of it since October.
I'm both happy and frustrated that it was that simple. Frustrated because if I knew what I was doing or looking at, I might have solved my own problem and saved the $260 I was charged (2hrs labor only). But I'm happy I didn't have to replace something more expensive.
I guess I post this here for anyone who at least gets the "36" code that it might be something simple and if you know where to look.

[Xatlatc]

Skillet,
How many times or how long do you have to press your start button to get the generator running? I usually hold the button down for maybe 6 to 8 seconds then pause for a few moments then try again. After about 4 times it starts and runs well.

[Blue~Go]

Great you got it sussed out. I have this "only half joking" think I say whenever something goes wrong with electrical on a trailer (and sometimes on an RV), which is "it's always a ground." Well, maybe not, but it is often a ground

[Skillet]

Skillet,
How many times or how long do you have to press your start button to get the generator running? I usually hold the button down for maybe 6 to 8 seconds then pause for a few moments then try again. After about 4 times it starts and runs well.

Now that it's properly running, I hold the stop button down to prime it (about 5sec) then press start. It'll crank another 5 sec or so and fire right up. When I was having the problems after the beach it was like you described. But it began to deteriorate and I suppose with the wire eventually losing total contact it would just turn and turn over without catching. I guess the bolt was backing out slowly or something is why it didn't just go out in one shot. My next prediction is that with it not running 100% since March, my next problem will be the carb gumming up. I'm going to exercise this sucka every week under load.

[Skillet]

Great you got it sussed out. I have this "only half joking" think I say whenever something goes wrong with electrical on a trailer (and sometimes on an RV), which is "it's always a ground." Well, maybe not, but it is often a ground

So where is this grounding wire/strap? I forgot to ask the mechanic. Is it on the backside or underneath? Something I can access when I have the panel open?

[kyidletime]

I'll be watching this thread, because I'd like to know that too.

[Xatlatc]

I didn't know the generator can be primed by holding the stop portion down prior to starting. I guess I should read the instructions better. Do you hear anything while priming, such as a fuel pump etc? Also, where can you read the codes? I have a scan gauge and again, I didn't know the genset had a plug to read codes like a vehicle.
Ditto on where is the ground?

[Blue~Go]

I'm no generator expert, so take this in that spirit, but...

Were they talking about the DC chassis ground? If so, that's (at least in the 2000 manual and also on my '99 in real life) on one of the three chassis ground lugs that is approximately under the closet (if you are lying on the ground looking up at the frame). There are there there; one is for the refrigerator; one is for the generator; and one is for a bunch of different little DC things in the coach on the passenger side circuits (lights, etc.). Being outside, it can be vulnerable to corrosion, or, I suppose loosening (it's just a bare wire end through a screw/pressure contraption).

Here is a screen shot from the 2000 manual showing it:

I don't *think* there is any separate 110 chassis ground specifically for the generator. There is the overall 110 chassis ground from the brown box. It's in a group of three that are similar to the ones shown above but under the shower. One is for the 110 panel; one is for the 12-volt panel; and one is for the smaller loads (lights etc.) on the driver's side circuits.

This part I'm not as sure about, but I believe there may be a neutral to ground bond (110) somewhere inside the generator, but I don't think that would be considered a "strap," and also I don't believe that would affect starting. So probably not a factor.

My guess would be that since it was a starting problem, it was the DC chassis ground. Perhaps another factor is that Chinook used a wire size/length that is below what Onan recommends. This results in more voltage drop during starting than is recommended (and is more noticeable in colder weather). So that wouldn't help, and would mean that any problem with any connection would be more noticeable.

[Skillet]

I didn't know the generator can be primed by holding the stop portion down prior to starting. I guess I should read the instructions better. Do you hear anything while priming, such as a fuel pump etc? Also, where can you read the codes? I have a scan gauge and again, I didn't know the genset had a plug to read codes like a vehicle.
Ditto on where is the ground?

No plug for a scan gauge. In my experiences it'll start flashing codes at you if you try several times with no success and then press the "stop" button. For me it will do it at the switch by the back door or on the generator itself. If I remember correctly it flashes "3" twice and then starts flashing for the actual code. You can then look the code up online or check the back of your manual.

Blue: I think I've narrowed it down for your comments. I called over and was told that the mechanic was going to check the a/c output from the breaker on the generator. He removed the top cover and noticed a bolt was missing where the breaker housing and ground wire for the fuel cutoff solinoid are bolted to the generator. He looked around in the enclosure and found the bolt laying there. Reinstalled it and started up/running fine.

[Blue~Go]

Blue: I think I've narrowed it down for your comments. I called over and was told that the mechanic was going to check the a/c output from the breaker on the generator. He removed the top cover and noticed a bolt was missing where the breaker housing and ground wire for the fuel cutoff solinoid are bolted to the generator. He looked around in the enclosure and found the bolt laying there. Reinstalled it and started up/running fine.

Aha, thank you for sussing it out. So okay, that's more of an "internal generator wiring" ground vs. a Chinook chassis ground. Don't know that I would have figured that out out either (pretty sure I wouldn't have). But now we'll all be checking that if we have a similar problem, you can bet.