Generator Starving for gas?

[Mister C]

• 2022 Jayco Alante 31V, Generator QG 4000 with 4.7hours of operation.
• I tried starting my generator after three months of no operation. It started then surged to a stop. Tried two more times to no avail.
• My first thought is no fuel so I manually primed using the switch at the generator, tried to start it, would not start, just cranked.
• I took the fuel line off at the carburetor end and observed only a few drops of fuel were in fuel line.
• With the fuel line off, I pressed the priming switch for 30 seconds, all that came out were drips of fuel. I could hear the pump fluttering, but no measurable fuel was exiting the fuel line.
• I then pulled the fuel line off the filter end and the fuel line was empty.
I then checked the fuel line all the way back to the fuel tank and there were no areas of crimping in the line.
o I then used a siphon to pull fuel to the filter end of the fuel line successfully, I then reattached the line and went to the carburetor end and siphoned fuel to that end. So now there is fuel all the way to the carburetor end
o With the lines full of gas, I re-attached the line to the carburetor, hit the primer switch for a minute
o I hit start, it started right up and then a minute and half later it surged to a stop.
o Pulled the fuel line off the carburetor end again, and it was empty.
o Re-siphoned a full line of gas through the fuel line to the carburetor end, reattached the fuel line, primed the line for 1 full minute, hit start, it started, and ran for 1 minute 52 seconds until is surged to a stop
o Pulled the fuel line off once again and the line was empty.
o For clarity, there is 12 volts at the pump solenoid, and it flutters when priming, there’s just no gas exiting the fuel line to the carburetor.
o May I assume the fuel pump is bad?
o What else might I be missing? Thanks in advance. P.S. Called Cummings and they were no help, since it's a 36 error code.

 

[Kevin Cooper]

I’m not an RV tech. From your description of events, it seems to be an electrical problem. When you push the stop button now, you get fuel. That means pump works. Then you start it, and it runs until it sucks the fuel out of the bowl and dies. So, when your generator is running, it sounds like a relay in the gen. controls is not closing while running to get power to the fuel pump. You could put your meter on the pump lead, and check for voltage with gen running to prove or disprove my theory.

 

[Michael Francois]

We had the same experience. We're told by Jayco service desk (back when they still answered the phone) that the generator does not draw fuel if the main tank is below 1/4 full. Never had a problem since.

 

[Kevin Cooper]

Also, a very good point.

 

[Mister C]

We had the same experience. We're told by Jayco service desk (back when they still answered the phone) that the generator does not draw fuel if the main tank is below 1/4 full. Never had a problem since.

Forgot to add the gas tank is 3/4rths full, on a 4-degree angle downhill from the generator

 

[craigav]

Keep in mind that even a new fuel pump cannot pump air (vapor). So if you hear the pump when priming, and each time the engine dies you find no fuel in the carb or fuel line, then what I would suspect is most likely as that there is still air in the fuel line. Also, with the pump at the generator, if there was a small leak in the fuel line then that could\would be where the air is coming from and likely wouldn't be seen dripping as that section of line would be under a vacuum instead of pressure.

I would inspect the fuel line very carefully and perhaps try to pull a 1/2 gallon through the fuel line via a syphon or similar and then see if the flow stops or any drips are observed while syphoning. Also, if you suspect the fuel line has a small hole in it and you have a compressor that you can adjust down to 2~3psi, you could try blowing air through the fuel line back into the tank. Be careful if you do this for several reasons, one of which is to be sure that there is no moisture at all in the air supply (compressor or hose, or even a very humid day). ~CA

 

[JimD]

Had a similar problem with my son's 5th wheel generator. Fuel pump just trickled fuel. Replaced the pump and verified the new one's operation. It pumped steadily. Problem solved.

 

[Mister C]

Keep in mind that even a new fuel pump cannot pump air (vapor). So if you hear the pump when priming, and each time the engine dies you find no fuel in the carb or fuel line, then what I would suspect is most likely as that there is still air in the fuel line. Also, with the pump at the generator, if there was a small leak in the fuel line then that could\would be where the air is coming from and likely wouldn't be seen dripping as that section of line would be under a vacuum instead of pressure.

I would inspect the fuel line very carefully and perhaps try to pull a 1/2 gallon through the fuel line via a syphon or similar and then see if the flow stops or any drips are observed while syphoning. Also, if you suspect the fuel line has a small hole in it and you have a compressor that you can adjust down to 2~3psi, you could try blowing air through the fuel line back into the tank. Be careful if you do this for several reasons, one of which is to be sure that there is no moisture at all in the air supply (compressor or hose, or even a very humid day). ~CA

Thank You. I'll pull a 1/2 gallon or so through the lines and see what happens when priming with the line disconnected from the carb. I was pretty careful to make sure there are no leaks all the way back to the tank, thanks for mentioning that.

 

[CAG-JAY]

One thing that if it were me, I would try is Seafoam to fog the fuel pump. Can't hurt at this point before tearing into things. Just from what you have said the clogging point seems to be at or behind the pump.

 

[Mister C]

One thing that if it were me, I would try is Seafoam to fog the fuel pump. Can't hurt at this point before tearing into things. Just from what you have said the clogging point seems to be at or behind the pump.

I literally just heard from another source to try the same thing. Can't hurt at this point. Thank you.

 

[Mister C]

Hi All, just following up with the fix to my issue. After many discussions and elements from each of you replies it turns out to be the Fuel Pump. Replaced it this morning and let it run for an hour with the AC on and it purred like new. This was an excellent challenge and I learned a lot.
Notes: The old pump only fluttered vs the new pump. The new pump made a much more robust pumping sound and actually vibrated as it was what seemed like pressurizing. This took roughly 5-8 seconds with dry carburetor bowl. The old pump always just fluttered, never pressurized.

Before replacing the fuel pump I tried to perform the seafoam fogging but the old pump would not take in the seafoam while priming. I was successful using a siphon and leaving it in the pump overnight but no success in keeping the generator running afterwards. The old furl pump still just fluttered with only a trickle of fuel exiting the pump.
So I bit the bullet and installed a new fuel pump. When priming the gas with the new pump the fuel jetted out of the fuel line so this certainly gave me the feedback I needed in that this was the right direction. FYI, I used the old filter since it only had 5 hours on it. To all replies, Thanks again.

 

[youracman]

Hi All, just following up with the fix to my issue. After many discussions and elements from each of you replies it turns out to be the Fuel Pump. Replaced it this morning and let it run for an hour with the AC on and it purred like new. This was an excellent challenge and I learned a lot.
Notes: The old pump only fluttered vs the new pump. The new pump made a much more robust pumping sound and actually vibrated as it was what seemed like pressurizing. This took roughly 5-8 seconds with dry carburetor bowl. The old pump always just fluttered, never pressurized.

Before replacing the fuel pump I tried to perform the seafoam fogging but the old pump would not take in the seafoam while priming. I was successful using a siphon and leaving it in the pump overnight but no success in keeping the generator running afterwards. The old furl pump still just fluttered with only a trickle of fuel exiting the pump.


So I bit the bullet and installed a new fuel pump. When priming the gas with the new pump the fuel jetted out of the fuel line so this certainly gave me the feedback I needed in that this was the right direction. FYI, I used the old filter since it only had 5 hours on it. To all replies, Thanks again.

Thanks for the follow up post, Mike. Helps us all via more "what fixed it" info in the archives for folks to search on; and all of us DIYers appreciate it.

Good times and safe travels to ya.............

 

[Mister C]

Thanks for the follow up post, Mike. Helps us all via more "what fixed it" info in the archives for folks to search on; and all of us DIYers appreciate it.

Good times and safe travels to ya.............

My pleasure Ed.

 

[Jagiven]

Not a solution to your current issue. It is recommended to run your genny at minimum once a month for 30-60 minutes under 50% load. Some people will turn on the AC or electric heater and watch some TV. Running keeps the fuel fresh in the line and in the Carb. Modern fuels are bad for old school carburetors.

 

[Mister C]

Sage advice I'll not ignore this winter...Thank you.

 

[CAG-JAY]

Good news!

 

[SanMarMor]

My 23 Precept is doing exactly this with my Onan 5500. The dealers replaced the fuel pump and said it worked. But when I got it home it didn’t. So I took it back (50 miles) and the tech verified it didn’t work, and verified no fuel pumping from the pump. So they ordered another pump, after a LOT of arguments about them not wanting the pay for the warranty. I took our RV home because we have three trips reserved (another 50 miles) and I have an appointment to take it back in July (another 50 miles). They said if this doesn’t fixed it, it’s probably won’t be covered under warranty again. This dealer has been a PITA dealing with warranty.

So I’m waiting for another pump to see if it will work. We’ve had the RV a year now, and the generator only ran the first three months.

 

[Retired mountain folk]

Just a side note. Don’t let it go three months without starting it. You will be replacing carburetors a lot. We make sure we start it every month, run for a while with a heavy load. Turn on air conditioner, lights, anything that will draw power. And yes, make sure you have lots of gas.they are all made to work that way. Good luck.

 

[DonC757]

My friend has a 2022 and he has had issues with his generator. They insulated the fuel line. Replaced an electric fuel pump. His will run for several hours when it’s hot and then it just shuts down. Wondering why you’re doing all this as it’s certainly still under warranty. Try to find a service center with an authorized Cummings repair technician. Most RV places won’t have one at all. They have a general RV mechanic that can change the oil, the air filter, the spark plug, etc. Hard to find. Good luck.

 

[DonC757]

Getting service for my 34G has been horrible. Awful. They just don’t work with you. Example – my radio touchscreen froze up. I called the radio manufacturer. They had me disconnect some wires and reset things and said Yep, you need a new radio. So I called the RV place where I bought my RV told him all this and the guy said bring it on up. I’ll have a radio here. I brought it there, the technician came and said Yep you need a new radio. Guess what, they did not have a radio. They said well let’s schedule an appointment to bring it in. Problem is I’m 100 miles away each way. I asked them to mail me the new Radio. Have it sent to me. Four Phillips screws to remove our radio. I could remove my radio and put a new one in in two minutes with a small Phillips screwdriver. I actually ended up just buying a new one and throwing it in there myself it was cheaper that way.