I looked at the J C Whitney fuel pump. It is nothing similar to the one on my generator. As a mechanical dummy I do not know if the JCW fuel pump is a satisfactory replacement. Any suggestions or opinions. Thanks.

Bite the bullet and install the Onan factory replacement....if thats the proven problem..

Hi, When I bought my Barth the owner gave me an extra pump for the 5000 onan gen. It came from Napa Number 3-7601 the 1 might be an 8 I can't make it out for sure,the box looks original. The pump is just like the original onan model. 12volt negative ground electric fuel pump. The info on the pump Bendex electric fuel pump . Might be cheaper. Good luck.

Ralph Glover 1976 Barth 27'

If I were you, I would buy a generic (Carter, Holley...) electric automotive type low pressure fuel pump for a carbureted engine (less than 15 psi or you will blow out the needle valve in the carb). This pump should be around $30-50. It doesn't matter if it looks like the old pump-as long as it pumps fuel and fits in the space where the old pump was located. You can plumb it with short pieces of rubber fuel line. There is no need for a $500 Onan pump.

If you checked your fuel pump when your fuel tank was low (less than 1/4 tank) it may not pick up any fuel. They use a higher fuel pickup in the fuel tank so that the generator won't run the engine fuel completely out and leave you stranded out in the woods. I would check the pump with at least a half tank of gas or unplug the intake hose on the pump and see if it will pick up gas from a jar.

$500 for an Onan fuel pump? Forget my advise! Go with Eddies idea...

I wanted to post an update and found this old thread to tag onto. I replaced my original (?) fuel pump with a $30 Facet from Pep Boys. I couldn't keep the generator running for more than a few minutes after that. I finally brought it to my Onan tech to troubleshoot. He said that the aftermarket pump quit running when the supply voltage dropped below 12VDC (the control board causes ~0.2 volt drop.) He ran an OEM pump on the bench down to 8VDC and it never quit. Bought ($80 w/10% club discount) and installed the OEM pump and the genset now runs as smooth as silk!

I learned the hard way also. Replace Onan parts with Onan parts. It's not worth the problems.

quote:

Originally posted by Phil Whalen:
I wanted to post an update and found this old thread to tag onto. I replaced my original (?) fuel pump with a $30 Facet from Pep Boys. I couldn't keep the generator running for more than a few minutes after that. I finally brought it to my Onan tech to troubleshoot. He said that the aftermarket pump quit running when the supply voltage dropped below 12VDC (the control board causes ~0.2 volt drop.) He ran an OEM pump on the bench down to 8VDC and it never quit. Bought ($80 w/10% club discount) and installed the OEM pump and the genset now runs as smooth as silk!

Phil, I'm having a little trouble understanding this. If the genset is running, it should be charging the battery, which means system voltage is 13.2 to 14.2, depending on the state of charge and your charger. Or do you just have the converter? Even so, voltage should be above 12. Have you monitored system voltage at the time that the genset shut down?

The idea of a fuel pump not working at less than 12 volts seems a little odd. I think my Kohler has a Facet pump. And my Honda RV6010 genset has what appears to be a Facet fuel pump. Sometime when I have nothing else to do, I will check how it works at lower voltages.

I've also had problems with the original equipment pumps giving out on my Kohler gen sets. I could not rationalize spending the $100.00 plus for a "Special " fuel pump so I asked the Kohler people here in Phoenix about it and they said that the only thng you had to make sure of was that either the pump was 3 psi or less or if it was a higher pressure pump that you used a fuel pressure regulator to reduce the pressure to 3psi max.

They explained that if you use a higher pressure pump you would likely over power the needle valve in the float bowl and cause the engine to flood from the over rich situation or cause leaks in the bowl gasket.
The carb wasn't designed for high pressure.

I had a 7psi electric pump at home so I opted to spend $20.oo for an adjustable fuel pressure regulator. The generator has worked fine for many years with this set up.

Bill - I didn't try to substantiate the tech's findings. He claimed that the voltage drop after the control board is normal at ~11.8VDC. He was pretty confident that the problem was in that after-market fuel pump. I paid him the $110 for his expertise and replaced the pump. That was all I did and it worked! (I guess I am a bit of a skeptic though, because I did try to run the genset on the old fuel pump after I picked the coach up from the shop... same results as before.)

Barry, someone in the past put a regulator on my Kohler, just like yours, so it sounds like you got good advice.

I've found over the years that there's usually a substitute part for the OEM part. Manufacturers subcontract suppliers to make their parts. Even Ferraris have some good old American TRW parts. If you have the time and inclination, you can find a substitute. I will not pay $35 for an Onan air filter, the $3.99 substitute from O'Reilly works just fine.