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Onan 4ky generator problems

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dennisl

RVF Regular
Joined
Jun 19, 2024
Messages
9
I have an older Jayco Class C with an Onan 4k generator. Ran it yesterday for about 30 minutes with house ac on. Ran great and then suddenly cut off and would not restart. I pulled the fuel line off at the carb and cranked it for several seconds - no fuel getting to the carb. Today I installed a new fuel pump with no improvement. I then disconnected the fuel line at the fuel filter and attached a short piece of fuel line there with the other end dipped into a small container of gas. Ran great so I suppose that means the fuel filter, fuel pump and carb are not the problem. I guess tomorrow I will drag my ancient carcass underneath to trace the fuel line back to the tank. Anyone here have any other suggestions as to what it might be. Oil level seems to be ok and mh gas tank is over half full. Any advice or suggestions much appreciated.
 
I have an older Jayco Class C with an Onan 4k generator. Ran it yesterday for about 30 minutes with house ac on. Ran great and then suddenly cut off and would not restart. I pulled the fuel line off at the carb and cranked it for several seconds - no fuel getting to the carb. Today I installed a new fuel pump with no improvement. I then disconnected the fuel line at the fuel filter and attached a short piece of fuel line there with the other end dipped into a small container of gas. Ran great so I suppose that means the fuel filter, fuel pump and carb are not the problem. I guess tomorrow I will drag my ancient carcass underneath to trace the fuel line back to the tank. Anyone here have any other suggestions as to what it might be. Oil level seems to be ok and mh gas tank is over half full. Any advice or suggestions much appreciated.
 
One thing I forgot to ask about. After installing the new pump I primed the pump for several seconds on a few occasions. Shouldn't a new pump be able to suck fuel thru an empty fuel line all the way from the gas tank to the generator?
 
I have an older Jayco Class C with an Onan 4k generator. Ran it yesterday for about 30 minutes with house ac on. Ran great and then suddenly cut off and would not restart. I pulled the fuel line off at the carb and cranked it for several seconds - no fuel getting to the carb. Today I installed a new fuel pump with no improvement. I then disconnected the fuel line at the fuel filter and attached a short piece of fuel line there with the other end dipped into a small container of gas. Ran great so I suppose that means the fuel filter, fuel pump and carb are not the problem. I guess tomorrow I will drag my ancient carcass underneath to trace the fuel line back to the tank. Anyone here have any other suggestions as to what it might be. Oil level seems to be ok and mh gas tank is over half full. Any advice or suggestions much appreciated.
How much fuel is in your tank? Most setups will not allow the Genset to access fuel if the tank is less than a 1/4 full.

Darrell
 
I have the same problem with the 4k onan on our class C. Plenty of fuel getting to the carb, but after 30 - 45 minutes, the generator shuts off. From what I've read, it's probably an over heating thing.
 
I have the same problem with the 4k onan on our class C. Plenty of fuel getting to the carb, but after 30 - 45 minutes, the generator shuts off. From what I've read, it's probably an over heating thing.
As stated above, NO fuel is getting to the carb.
 
One thing I forgot to ask about. After installing the new pump I primed the pump for several seconds on a few occasions. Shouldn't a new pump be able to suck fuel thru an empty fuel line all the way from the gas tank to the generator?
It should be able to pull the fuel. When I had a gas MH, I had the fuel pump fail and the symptoms were that it would run, then quit. But once I replaced the pump, and cranked it a bit, it did start.

But from what you are saying, the new pump appears to be working? I would be curious if there is a problem with the line. Puzzling.

Maybe an issue with where the line goes into the tank?
 
It should be able to pull the fuel. When I had a gas MH, I had the fuel pump fail and the symptoms were that it would run, then quit. But once I replaced the pump, and cranked it a bit, it did start.

But from what you are saying, the new pump appears to be working? I would be curious if there is a problem with the line. Puzzling.

Maybe an issue with where the line goes into the tank?
I think you are probably right. My next step is to reluctantly go underneath and trace the line from the tank to the genny. We have a lot of squirrels and chipmunks around here so a chewed line would not surprise me. Just hope the problem is one I can get to. We will see how it goes. Thanks
 
As stated above, NO fuel is getting to the carb.
Well, you ran it yesterday for about 30 minutes with house ac on. So I thought fuel would be getting to the carb........
 

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