Generator keeps shutting off

[jpannier]

We took our MH from the east coast of Florida to the west coast to get away from the hurricane. We are parked in my cousin's driveway and have no shore power. So, in order to keep my residential refrigerator running I was using the generator. I left the generator run all night but, later in the day it stopped running. I have plenty of gasoline and I checked the oil (one website said they automatically cut off if the oil pressure gets low) and it is fine as well. I started it probably six times today and it starts right up. However, after about 30 minutes it stops. If it wasn't for the food in my refrigerator I would just hit the 12 volt cutoff switch and take it to my repair facility when I go back to the east coast. Wondering if anyone has any thoughts on why it keeps shutting off. Also, anyone have any idea if the fridge will stay cold enough overnight?

[wolverine68]

wolverine68 wrote:

wolverine68 wrote:

wolverine68 wrote:

bounder39zman wrote:
deal with this all the time. When gen shuts off, place couple paper towels under carb, open bowl drain screw, see if much fuel comes out. If only couple drops, or none, then either fuel pump is getting hot and quits pumping, or control board is getting overheated, and quits sending power to fuel pump. Usually displays fault code 36, but have seen other fault codes if control board is problem. There is third condition that will cause these symptoms, that being hot air is being recirculating to air intake and gen temperature in housing is getting so hot that gas is boiling in fuel line and carb, causing shut down. This problem seems to be much more common last couple years, and I can't prove it, but I think fuel boiling point is lower than used to be with the crappy fuel we have to use these days

That sounds like a great "next step" in trouble shooting. Thanks!

Thanks Bounder39zman. You nailed it. Minimal fuel in float bowl after it shut down. Compared it to a properly filled bowl after restart and it only had about 1/10 of the amount as normal. Now I just have to find a reasonably priced fuel pump lol.

Replaced the fuel pump and it fired right up. I realized that I was still on shore line so I shut it down after about 10 seconds and it would not start after.It would not even fire; just crank. I checked for fuel at the carb-good, spark-good. I used some starting fluid in the air inlet and it would run on that so I pulled the carb and inspected and blew out all the passages, reinstalled and still no go. Today I disconnected the wire leading to the solenoid on the bottom of the carb and using a jumper wire I could get it to run but only for about 1 second at a time. Any ideas? Thanks in advance.

Disregard. I removed the stating solenoid and mother board, dielectric greased all the connections, put it back together and it ran as good as new. I will newer understand how it ran for a good 10 seconds before it decided to give me grief.Thanks for all your help gentlemen!

[wolverine68]

wolverine68 wrote:

wolverine68 wrote:

bounder39zman wrote:
deal with this all the time. When gen shuts off, place couple paper towels under carb, open bowl drain screw, see if much fuel comes out. If only couple drops, or none, then either fuel pump is getting hot and quits pumping, or control board is getting overheated, and quits sending power to fuel pump. Usually displays fault code 36, but have seen other fault codes if control board is problem. There is third condition that will cause these symptoms, that being hot air is being recirculating to air intake and gen temperature in housing is getting so hot that gas is boiling in fuel line and carb, causing shut down. This problem seems to be much more common last couple years, and I can't prove it, but I think fuel boiling point is lower than used to be with the crappy fuel we have to use these days

That sounds like a great "next step" in trouble shooting. Thanks!

Thanks Bounder39zman. You nailed it. Minimal fuel in float bowl after it shut down. Compared it to a properly filled bowl after restart and it only had about 1/10 of the amount as normal. Now I just have to find a reasonably priced fuel pump lol.

Replaced the fuel pump and it fired right up. I realized that I was still on shore line so I shut it down after about 10 seconds and it would not start after.It would not even fire; just crank. I checked for fuel at the carb-good, spark-good. I used some starting fluid in the air inlet and it would run on that so I pulled the carb and inspected and blew out all the passages, reinstalled and still no go. Today I disconnected the wire leading to the solenoid on the bottom of the carb and using a jumper wire I could get it to run but only for about 1 second at a time. Any ideas? Thanks in advance.

[DFord]

😉

[jpannier]

Gonna' try replacing the fuel pump and filter. Sounds like that may be the problem and the parts are only about $35. See what happens.

[maillemaker]

I highly recommend you cruise over to:

https://www.smokstak.com/forum/forumdisplay.php?f=1

For Onan help.

They are not very hard to work on once you get them out on a work bench. For me the thing was a black box until I determined I was tired of dropping $500 every time it needed service.

Turns out my old 4BGE you can replace every electrical thing on it for less than $200 (starter, plugs, ignition control module, distributor, condenser), and you can replace the voltage regulator for $150 and the control board for $200.

The engines themselves are pretty bullet proof given how little they run.

The Achilles heal of my genny is the little plastic propeller they put on the main shaft in between the engine and the gen head. This has the magnets on it that the ECM picks up. If a mouse builds a nest in there and you try to start it, it will shear off the rotor arms. It has not happened to me, but if it does you have to split the genny in half to fix it.

[jpannier]

It is an Onan RV QG 5500. I did figure out how to read the fault codes. It is 36. Sounds like it may need servicing which I did not expect. I bought it used from LaMesa last December. They told me at the time that everything had been serviced. I haven't used it much since I bought it but, I do exercise it monthly.

[jpannier]

Couldn't get to the plug on the refrigerator without taking it out. They should have a door on the outside to access it.

[lane_hog]

wolverine68 wrote:
Now I just have to find a reasonably priced fuel pump lol.

Lots of options for under $50 including the filter. Amazon has several bundles with the Airtex E11007 pump which is a direct replacement for the Onan OEM pump, and I've seen actual Onan filters for under $10. The Podoy version looks similar, but has a 90* angle fuel inlet barb which doesn't appear to work in the Onan case.

[Kpackpackkelley]

Just go by the model number and spec letter to get the right one they are not to high.

[wolverine68]

wolverine68 wrote:

bounder39zman wrote:
deal with this all the time. When gen shuts off, place couple paper towels under carb, open bowl drain screw, see if much fuel comes out. If only couple drops, or none, then either fuel pump is getting hot and quits pumping, or control board is getting overheated, and quits sending power to fuel pump. Usually displays fault code 36, but have seen other fault codes if control board is problem. There is third condition that will cause these symptoms, that being hot air is being recirculating to air intake and gen temperature in housing is getting so hot that gas is boiling in fuel line and carb, causing shut down. This problem seems to be much more common last couple years, and I can't prove it, but I think fuel boiling point is lower than used to be with the crappy fuel we have to use these days

That sounds like a great "next step" in trouble shooting. Thanks!

Thanks Bounder39zman. You nailed it. Minimal fuel in float bowl after it shut down. Compared it to a properly filled bowl after restart and it only had about 1/10 of the amount as normal. Now I just have to find a reasonably priced fuel pump lol.

[wolverine68]

bounder39zman wrote:
deal with this all the time. When gen shuts off, place couple paper towels under carb, open bowl drain screw, see if much fuel comes out. If only couple drops, or none, then either fuel pump is getting hot and quits pumping, or control board is getting overheated, and quits sending power to fuel pump. Usually displays fault code 36, but have seen other fault codes if control board is problem. There is third condition that will cause these symptoms, that being hot air is being recirculating to air intake and gen temperature in housing is getting so hot that gas is boiling in fuel line and carb, causing shut down. This problem seems to be much more common last couple years, and I can't prove it, but I think fuel boiling point is lower than used to be with the crappy fuel we have to use these days

That sounds like a great "next step" in trouble shooting. Thanks!

[bounder39zman]

deal with this all the time. When gen shuts off, place couple paper towels under carb, open bowl drain screw, see if much fuel comes out. If only couple drops, or none, then either fuel pump is getting hot and quits pumping, or control board is getting overheated, and quits sending power to fuel pump. Usually displays fault code 36, but have seen other fault codes if control board is problem. There is third condition that will cause these symptoms, that being hot air is being recirculating to air intake and gen temperature in housing is getting so hot that gas is boiling in fuel line and carb, causing shut down. This problem seems to be much more common last couple years, and I can't prove it, but I think fuel boiling point is lower than used to be with the crappy fuel we have to use these days

[wolverine68]

DFord wrote:
> Onan Flash Codes

Once again I ask, is the light in the start button flashing? If so, there's a trouble code stored and should be retrieved and decoded to reveal the reason the generator is stopping.

Has the OP ever revealed the model of the generator vintage so that an educated answer can be given?

If you are referring to my situation, see my post above: "This is the problem with my adding to an existing thread lol. I'm not sure who the questions are for. My genny is an Onan 4000, 4KY spec K. No low oil level sensor but the oil level is good. Code occasionally show "36" which is "engine shut down without command". I do have fuel and spark after shut down but still won't restart until it cools down. "

[DFord]

> Onan Flash Codes

Once again I ask, is the light in the start button flashing? If so, there's a trouble code stored and should be retrieved and decoded to reveal the reason the generator is stopping.

Has the OP ever revealed the model of the generator vintage so that an educated answer can be given?