First - I am not what you might consider handy and so I generally pay to have things done.My MH has a 4KW Onan Microquiet gas genny. I purchased the MH from folks who rarely used it and found all the systems they had to learn confusing. The generator would not start and I factored that into my offer. Preparing for last summer travels, I took the MH to a Cummins/Onan factory run RV facility in Ft Myers. They replaced the carb and had it running and returned to me in a half hour or so. I then traveled using the gen set frequently over the next 6 months. On my last night out, I used the genny for a couple of hours for AC and some TV and then turned it off before retiring for the night. I finished my trip the next day and arriving at home early afternoon, I tried to start the generator. It would not start and that was only 8 hrs or so after having been started and run the night before. It hasn't started since. It will turn over and will run a few seconds if I use the starter spray.So I'm a bit curious why a genset, with about 100 hrs on it, would suddenly not start in such a short period of time. I don't mind getting it fixed but would like to be a bit more educated on what might be wrong and how long a fix should last. Surely a fix should last more than 6 months at a time? What say you?

Start with simple: oil level, primed, stuck choke, clear air intake. Not an expert, just own several engines.

First thing. How much fuel is in the motorhome tank? The generator usually draws fuel from the tank for the engine.The pickup is about 1/4 tank above the bottom of the tank, so you can't let the generator use up all the fuel and strand you.Maybe after you ran the generator and then drove home, you dropped the fuel level below the generator pickup.Go fill the gas tank, at least 1/2 full and see what happens.If that does not solve the problem, do what coolbreeze01 said, check your oil level in the generator. Also make sure the fuel filter is clean.It sounds like you ran the fuel in the tank too low.Let us know if that solved your problem. Always do the cheap, easy things first, it's often something simple.

Thanx. Coolbreeze01: If it were a stuck choke, non clear intake, low oil level, would it run when sprayed with the starting fluid? And if so, would they account for it running well just hours before and then totally refusing to start?Gbopp: Fuel tank is at 3/4 full (probably 35-40 gal left out of a 55 gal tank). I filled up in the town where I overnighted, ran the genny for 2 hours and then drove the last 125 miles home.

avan wrote:Gbopp: Fuel tank is at 3/4 full (probably 35-40 gal left out of a 55 gal tank). I filled up in the town where I overnighted, ran the genny for 2 hours and then drove the last 125 miles home.Okay, my theory is out the window. Did you replace the fuel filter for the generator?Maybe it's not getting fuel.Hopefully someone has a better answer or idea of what's causing your problem.

No, I haven't replaced the fuel filter. But I would hope that when I brought it to the Cummins/Onan facility, told them it was a "new to me" generator, that it wouldn't start and to service and fix it, that they would have replaced whatever needed replacing. The gen set had 32 hours on it at the time. When I get over to the MH later this week, I'll pull the invoice and see what, in addition to the carb, they billed me for. I'm not upset about having it serviced again. I was just surprised by the abruptness and totality of the failure without any forewarning - no hard starts, no burping, no rough idling etc. And now since it hasn't started since I got back in October, I suspect that the carb will be clogged again just because of the idleness and am wondering if it is replaced again, should I expect a working life in excess of 6 months?

Genset issue | Good Sam Community

the_bear_II
Explorer
Feb 29, 2016
To me it sounds like the fuel filter is clogged. That's why it will run on the starting fluid but dies because no fuel is coming through. Brand new fuel filters can clogged if the fuel or tank is contaminated. With you travelling you may have shook up some debris or gotten bad gas somewhere.

I would replace the fuel filter first.
ksg5000
Explorer
Feb 29, 2016
If you provide the exact model number and spec for your Onan chances are someone will provide you with link to on-line repair manual which should have trouble shooting section.

Sounds like fuel starvation issue - maybe bad fuel pump, clogged fuel filter, fuel line issue?
avan
Explorer
Feb 29, 2016
No, I haven't replaced the fuel filter. But I would hope that when I brought it to the Cummins/Onan facility, told them it was a "new to me" generator, that it wouldn't start and to service and fix it, that they would have replaced whatever needed replacing. The gen set had 32 hours on it at the time. When I get over to the MH later this week, I'll pull the invoice and see what, in addition to the carb, they billed me for.

I'm not upset about having it serviced again. I was just surprised by the abruptness and totality of the failure without any forewarning - no hard starts, no burping, no rough idling etc. And now since it hasn't started since I got back in October, I suspect that the carb will be clogged again just because of the idleness and am wondering if it is replaced again, should I expect a working life in excess of 6 months?
gbopp
Explorer
Feb 29, 2016
avan wrote:

Gbopp: Fuel tank is at 3/4 full (probably 35-40 gal left out of a 55 gal tank). I filled up in the town where I overnighted, ran the genny for 2 hours and then drove the last 125 miles home.

Okay, my theory is out the window. Did you replace the fuel filter for the generator?
Maybe it's not getting fuel.

Hopefully someone has a better answer or idea of what's causing your problem.
avan
Explorer
Feb 29, 2016
Thanx.
Coolbreeze01: If it were a stuck choke, non clear intake, low oil level, would it run when sprayed with the starting fluid? And if so, would they account for it running well just hours before and then totally refusing to start?

Gbopp: Fuel tank is at 3/4 full (probably 35-40 gal left out of a 55 gal tank). I filled up in the town where I overnighted, ran the genny for 2 hours and then drove the last 125 miles home.
gbopp
Explorer
Feb 29, 2016
First thing. How much fuel is in the motorhome tank? The generator usually draws fuel from the tank for the engine.
The pickup is about 1/4 tank above the bottom of the tank, so you can't let the generator use up all the fuel and strand you.
Maybe after you ran the generator and then drove home, you dropped the fuel level below the generator pickup.
Go fill the gas tank, at least 1/2 full and see what happens.

If that does not solve the problem, do what coolbreeze01 said, check your oil level in the generator. Also make sure the fuel filter is clean.

It sounds like you ran the fuel in the tank too low.

Let us know if that solved your problem. Always do the cheap, easy things first, it's often something simple.
coolbreeze01
Explorer
Feb 29, 2016
Start with simple: oil level, primed, stuck choke, clear air intake. Not an expert, just own several engines.

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