Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Elliott on May 30, 2025, 07:37:30 pm

Title: Oil pressure switch woes
Post by: Elliott on May 30, 2025, 07:37:30 pm
I replaced the oil pressure switch on my propane onan generator. The switch I used has mostly the same specs, the same low pressure value and a slightly higher high pressure value. There is an appropriate amount of oil in it, but it won't let the generator turn on. When I bypass it (see attached picture) it works just fine. Are there any common mistakes one might make when installing a new one?

Title: Re: Oil pressure switch woes
Post by: craneman on May 30, 2025, 07:55:18 pm
Did the old one fail or was it just leaking?
Title: Re: Oil pressure switch woes
Post by: Elliott on May 30, 2025, 07:59:30 pm
Did the old one fail or was it just leaking?
I Was having issues with keeping the generator running while driving down the road (but it worked fine when stationary) so it was something I replaced in an attempt to resolve that issue
Title: Re: Oil pressure switch woes
Post by: craneman on May 30, 2025, 08:08:51 pm
Is the new switch normally open? I don't understand the same low and high values you posted. It should only have a low pressure open circuit. There is only one wire and breaking the circuit shuts down the engine.
Title: Re: Oil pressure switch woes
Post by: Elliott on May 30, 2025, 08:32:50 pm
Is the new switch normally open? I don't understand the same low and high values you posted. It should only have a low pressure open circuit. There is only one wire and breaking the circuit shuts down the engine.
You know I don't know, I replaced it a long time ago but didn't have any propane to test until recently. Should t be NO or nc?
Title: Re: Oil pressure switch woes
Post by: Elliott on May 30, 2025, 10:13:26 pm
So after MUCH sleuthing, I was able to determine the old part# for the pressure switch on these coaches is  309-0237 NOS. I just ordered one to the tune of about $50. This is for a 6.5 NH-3cr/16004p gen set from the late 80's

I have not been able to find a more modern part # for a replacement but here are the specs for it:  pressure sending switch 8-10psi 1/8"-27 threads NOS

Posting this for the next guy and will follow-up to confirm it works