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

Gjac
Explorer III
Mar 03, 2016
Check the simple things first. Pull the spark plug wire off first an see it you have spark? Disconnect the fuel line to the carburetor and crank the eng are you get a steady stream of fuel out of the fuel pump? If you can answer these two questions your problem will be easier to diagnose.
johntank
Explorer
Mar 03, 2016
I will go with a bad fuel pump as it had been running less than 12 hours before hand, now that it has been sitting for 6 months I will say not only do you need a fuel pump, but the carb cleaned too.
TyroneandGladys
Explorer
Mar 02, 2016
Sounds wacky but try starting your RV leave it running and after a few minutes while still running try the generator. If generator starts let run for a few minutes and shut off RV but leave generator running for a while. Do not understand but has worked for us.
avan
Explorer
Mar 02, 2016
Ah... you're right on that. When I got back in Oct and the genny stopped working, I did put it in storage. I've gone to the storage lot perhaps a dozen times since Oct and tried to start it but without success. So I am well aware that 6 months of idleness hasn't done it any good and perhaps more harm. And that's OK. I don't have a problem spending the money to get stuff fixed especially for problems I may have exacerbated. I will be going back to Cummins in the next month to have it fixed before I start wandering again. I just thought how it died (virtually overnight) was strange and was seeking opinions. Also I was thinking before I show up at Cummins again, maybe I should get a bit of education, vis a vis what might need fixing, so that I don't appear as mechanically stupid as I really am. :B :B
westend
Explorer
Mar 02, 2016
Yes, I understood your use of the genset on the road. You also stated that you left it in storage for 6 months without running it or am I wrong on that?
avan
Explorer
Mar 02, 2016
westend wrote:

...but I'd still suggest you use the one working digit to start your genset more frequently. And, check that oil!
Without going back and rereading the entire thread, I thought I had said that I used the genny all summer up to and including my last night on the road only to have it not start the following day. To be more clear, I had the genset serviced the second week of April 2015 by Cummins/Onan factory facility. I left for the summer a week later. From then to when I got back in Oct, I put on 60+ hours on the generator pretty much evenly spaced. It was well exercised at least once per week - which is more than the working digit was :B I will check the oil when I get back to the storage facility as I was not aware that there is some sort of low oil level cut off switch.
westend
Explorer
Mar 02, 2016
Westend, I'm pleased to let you know that I only have 9 thumbs as I have worked real hard over the decades to exercise and retain my right hand middle finger.

Can't help you with genetic impairments but I'd still suggest you use the one working digit to start your genset more frequently. And, check that oil!
BruceMc
Explorer III
Mar 01, 2016
DrewE wrote:
BruceMc wrote:

One thing to check on the pump - push and hold your start button to the off/prime position, and listen for clicking from the pump after about 5 seconds. If you have no clicking sounds, the pump has probably failed.

I understand the prime function which you describe is not universal among the Onan 4KY generator sets. I'm not sure if it's a matter of what year the generator was made, or if it's an option from the factory, or what. I do know that mine has no prime function (and I rather wish that it did), but operates just fine without any evident fuel pump issues.

Interesting. We've had two now, both are standard 4KY sets, both have the same functionality. (build dates approx 1999 and 2015)
I've seen many others recommend the stop/prime function on this board when they are having problems starting their units, so had accepted this was pretty much a standard function on these models.

I learn something new every day.
DrewE
Explorer II
Mar 01, 2016
BruceMc wrote:

One thing to check on the pump - push and hold your start button to the off/prime position, and listen for clicking from the pump after about 5 seconds. If you have no clicking sounds, the pump has probably failed.

I understand the prime function which you describe is not universal among the Onan 4KY generator sets. I'm not sure if it's a matter of what year the generator was made, or if it's an option from the factory, or what. I do know that mine has no prime function (and I rather wish that it did), but operates just fine without any evident fuel pump issues.
BruceMc
Explorer III
Mar 01, 2016
Fuel pumps have a habit of failing on these units. Mine was running fine until one day, it didn't run. From your symptoms, it runs while being fed a source of fuel (the starting fluid), but dies otherwise. I would suspect the pump.

The filter might be clogged, but they'll usually give you an indication of that - it runs under no load, but it either struggles or dies under load as it is trying to pull more fuel than the filter will pass.

One thing to check on the pump - push and hold your start button to the off/prime position, and listen for clicking from the pump after about 5 seconds. If you have no clicking sounds, the pump has probably failed.

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