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Re: [GMCnet] Onan - Vapor Lock? [message #178454 is a reply to message #178444] Mon, 30 July 2012 20:42 Go to previous messageGo to previous message
ljdavick is currently offline  ljdavick   United States
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma:
Senior Member
Rob,

You didn't mention your fuel lines. Although unlikely, could they deform when hot and expose a crack letting air into the fuel pump?

I just think it has to be before the electric pump, assuming the pump isn't tired or the voltage to the pump is low.

Also the hoses to the Onan get no love and they see more movement than other hoses.

Larry Davick

On Jul 30, 2012, at 6:04 PM, "Rob Mueller" <robmueller@iinet.net.au> wrote:

> G’day,
>
> It seems that whenever the OAT gets to the mid nineties the Onan plays up. When the gas is "cold" it runs just fine. As the day
> heats up or if we drive with it on it starts to hunt and then finally shuts down. If I try to restart it immediately no joy but if I
> let it sit for about 5 minutes I will start and run for a few minutes then it dies again.
>
> When I was here in February I disassembled the carb and cleaned it thoroughly which must be true as when it's cool it runs PERFECTLY
> with a voltage output of 120.
>
> Last week before we left I removed the fuel pump and disassembled it. The "piston" moved up and down in the "bore" nicely, both
> plastic check valve balls were in fine shape and moved easily.
>
> I removed the solenoid at the inlet to the pump as I reckoned it was one thing less to fail.
>
> I installed a Pertronics mod a couple of years ago and a new Onan coil.
>
> I really think this is a vapor lock problem - it was 97° in Carlsberg, NM today,
>
> Oh yeah, I did check the fuel level in both tanks and both above 1/2.
>
> As they say in this neck of the woods - any idears?
>
> Regards,
> Rob M.
> USAussie - Downunder
>
> PS - SURE GLAD I INSTALLED A SECOND ROOF AIR LAST YEAR!
>
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Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy

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