Does anyone have a step by step process to replace the fuel pump on an Onan 4KY? Upon testing my genny in the hot weather yesterday, it ran for about 10 minutes under load, then abruptly quit.The fuel tank is within a gallon or two of being full, so it's not running out of gas.After letting it cool down for 20-30 minutes, it restarted and ran fine for a while before I shut it down.Today, we have another hot day (95°), so I thought I'd test it. It started fine, and after a few minutes, I loaded it with the rooftop air. It ran for about 10 minutes and quit again.I pulled the cover thinking it would have some trouble codes, but alas, the red light was, well, not red at all.Running the prime, it sounded real wimpy, very quiet. I pulled the fuel line at the carb, no gas. I aimed it at a bucket, then pushed prime. Wimpy sound, NO fuel.Again, after letting it cool for 20 minutes or so, I tried priming again - normal pump noise. The generator started with a bit of trouble, but of course, the float bowl was empty. Once the air was flushed, it ran fine again. I shut 'er down.The filter was replaced about a year ago, and other than maintenance runs and about a half hour last summer, it hasn't seen much run time. I replaced the pump in the main fuel tank last winter, and the tank was surprisingly clean, so I'm ruling out the filter.Onan part numbers: Pump #149-2311-02, filter #1492457Thanks in advance!--Bruce.

Definitely a fuel pump issue had mine replaced under a warranty. My symptoms were identical to yours.I know it only took the guy about 2 hours total to replace it though.

I am having a similar problem.Changed fuel filter, spark plug air filter and changed the oil.Gen runs with or without a load for about 20 min. Starts to surge a little than shuts down. I get a 36 code.I have flushed carb out with carb cleaner. Added Sea Foam to MH gas tank.Checked fuel line. Drained carb using the drain screw outlet. I get clean gasI like the old carbs that had adjustment screws on them. I see non on this one. Except for governor. I show 120 volts and 60/62 hertz. I see the fuel pump. But not the 2 screws that hold it in place. What a PITA to work on.

I had exactly the same thing happen about 5 years ago. A new fuel pump (same number as yours) resolved the problem.You probably already know that the pump is beyond and under the control board on the left side of the generator. It is visible in this picture.1. For safety's sake, disconnect shore power and also the ground wire from your house batteries. Verify that the generator won't crank. If it does disconnect the MH engine starting battery ground wire.2. Disconnect the fuel line where it connects to the filter and plug the line to keep gas from dripping.3. Remove the large red wire from the start solenoid and unbolt the solenoid to get it out of the way.4. Remove the control board (2 #30 Torx screws)5. There is one #30 Torx screw holding the pump foot to the bottom pan. The other foot on the pump is held in a slot in the bottom pan.6. Disconnect the pump discharge hose and power wire.7. Do the above in reverse order to install the new pump.Easy job.

Cool, I was wondering if there was a third (or more) torx anchoring the logic board. That was my plan of attack - remove power cable, insulate (it's a pain to disconnect the other end, easier to wrap this end with tape)remove logic board remove fuel line, plugremove fuel filter (optional)One torx holds down the pump, the other side is a tab in a slot.disconnect hose and powerleads, at it should be free.Ok, I now have a plan of attack, will stop by and order a new pump & filter tomorrow.Thanks!

One additional thought - After replacing my pump and filter and putting everything back together, I discovered a very small gas leak at the threaded connection where the filter screws onto the pump. I took it apart and applied a small amount of plumber's pipe dope (not teflon tape) to the threads, being very careful to keep the dope away from the end so it wouldn't get into the pump.

Onan 4KY fuel pump replacement method? | Good Sam Community

24 Replies

BruceMc
Explorer III
Jul 02, 2013
Cool, I was wondering if there was a third (or more) torx anchoring the logic board.

That was my plan of attack -
remove power cable, insulate (it's a pain to disconnect the other end, easier to wrap this end with tape)
remove logic board
remove fuel line, plug
remove fuel filter (optional)
One torx holds down the pump, the other side is a tab in a slot.
disconnect hose and powerleads, at it should be free.

Ok, I now have a plan of attack, will stop by and order a new pump & filter tomorrow.

Thanks!
CloudDriver
Explorer
Jul 02, 2013
I had exactly the same thing happen about 5 years ago. A new fuel pump (same number as yours) resolved the problem.

You probably already know that the pump is beyond and under the control board on the left side of the generator. It is visible in this picture.

1. For safety's sake, disconnect shore power and also the ground wire from your house batteries. Verify that the generator won't crank. If it does disconnect the MH engine starting battery ground wire.

2. Disconnect the fuel line where it connects to the filter and plug the line to keep gas from dripping.

3. Remove the large red wire from the start solenoid and unbolt the solenoid to get it out of the way.

4. Remove the control board (2 #30 Torx screws)

5. There is one #30 Torx screw holding the pump foot to the bottom pan. The other foot on the pump is held in a slot in the bottom pan.

6. Disconnect the pump discharge hose and power wire.

7. Do the above in reverse order to install the new pump.

Easy job.
rvten
Explorer
Jul 02, 2013
I am having a similar problem.
Changed fuel filter, spark plug air filter and changed the oil.
Gen runs with or without a load for about 20 min. Starts to surge a little than shuts down. I get a 36 code.
I have flushed carb out with carb cleaner. Added Sea Foam to MH gas tank.
Checked fuel line. Drained carb using the drain screw outlet. I get clean gas
I like the old carbs that had adjustment screws on them. I see non on this one. Except for governor. I show 120 volts and 60/62 hertz. I see the fuel pump. But not the 2 screws that hold it in place. What a PITA to work on.
chinook507
Explorer
Jul 02, 2013
Definitely a fuel pump issue had mine replaced under a warranty. My symptoms were identical to yours.

I know it only took the guy about 2 hours total to replace it though.

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Onan 4KY fuel pump replacement method?

24 Replies

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