Community Forums

mannebk · 02-19-2025, 05:38 AM

hi there

So, I'm going a lot up and down, altitude wise... technically I would need to change the jetting every time. well I don't do it. so my genset runs rich most of the time. I'm sick of that smell.

therefore either I convert to propane... while I own propane dual fuel cars, several actually, and do absolutely like it, that's only something i would considering on an EFI driven engine... i owne one with Venturi mixer, its a PITB... while a genset never has idle cut-off like cars, it sill doesn't like lean conditions. and who to tell you if your lean or not?

or I get an EFI on my 5kw genset. (and then a one Cylinder dual fuel LPG conversion?)

what's your thoughts about it?

i need to take it out anyway. exhaust gets modified, need to convert to split phase, new rubber mounts. and an oil leak that needs fixing.

thanks

mannebk · 02-19-2025, 05:43 AM

ps: I don't care for doomsday reliability... my MH engine is EFI anyway. and IMHO, if doomsday comes, I've got other problems than my RVs genset... so please don't elaborate on doomsday and points and such.

that's just not a basis for this decision, hence needs no discussion here. especially since im clearly aware of the issue.

I'm just sick of the rich smell, that depending on wind makes it into my MH....

And, yes I'm changing the exhaust due to that anyway, but id also prefer the engine to run on perfect mixture, as that safes fuel and maintenance.

yes I'm aware that probably won't pay off. even being only able to do some basic calculations :-)

and also yes to I've run liquefied petroleum gas systems on air-cooled engines... I've been using engine oil to heat the gas before the evaporator. just takes longer to switch over. or needs custom made parts on the evaporator to add an oil galery for keeping it above freezing. or an electric heat element... plenty of solutions.

Mark_K5LXP · 02-19-2025, 05:49 AM

Quote:

Originally Posted by mannebk

technically I would need to change the jetting every time

It's assumed then you don't have one of these? Standard equipment on Onan/Cummins:

Quote:

either I concert to propane...or I get an EFI on my 5kw genset.

There are some retrofit kits for propane, I've never seen a retrofit kit for EFI. Sounds ambitious. I'm thinking if yours doesn't have a user adjustable altitude tweaker, fitting a carb that does, or even a CV carb might be a more attainable goal.

Mark B.
Albuquerque, NM

mannebk · 02-19-2025, 04:55 PM

Mark, thanks for the input.

I fiddled with the genset a bit, as it did not produce power in the beginning... sure, 70h on the meter, probably not run in 20 years, eventually it came around. but while fiddling with it I haven't seen such an adjustment thingy...

changi carb would be an idea

but ive found some single engine EFI w spark conversion kits, while not specifically made for my genset, they come with all one needs ...

so its just, one has do do thr conversation, preferably clean, not hack it up style.

yeloduster · 02-20-2025, 06:58 AM

Manny,

There are a bunch of Chinese made reproduction carburetors for Onan generators sold on Amazon for ≈$50. I've read where people bought these carbs and had good results.

If possible find the model number tag on your generator and buy a carb that works.

I've not bought a reproduction carb for an Onan but I did buy a cheap carb from Amazon for a Kymco motorcycle. The carb worked better than the original. The carb from Amazon was a little bigger bore and produced better power and it had a better choke system than the original Kymco carb.

The original carb for my 5500 Marquis Gold Onan generator has the altitude adjustment. The altitude adjustment is not critical. Mine works fine at from 5000' to 10000' on the same setting. If I go below 5000' I adjust it for smoothest running. I live in Colorado so it is adjusted for high altitude most of the time.

d23haynes57 · 02-20-2025, 07:32 AM

I don't know what model you have but thinking it is an older unit that still has a side valve engine. These engines have poor combustion performance and typically have to run a bit rich. For the most part 4% to 6% CO is normal. If you do get them to run leaner besides poor performance, you will burn up the valves and pistons. They are stinky engines.
Why those Genturi exhaust extensions were so popular. The stink is mostly unburned fuel and some oil but the larger danger is CO.

David 70 · 02-20-2025, 07:34 AM

On my 318 John Deere Garden tractor with the 18hp two-cylinder Onan I kept having trouble with the points/condenser. I found an electronic type of ignition. It is a different type of conversion than I have ever seen but it cured the problem. I don't know where I got it but it cured the problem. Just google it and see what is out there.

mannebk · 02-22-2025, 08:46 AM

this is the one.

its runing strong at 203h total time. but oh my gosh, the smell i had to endure the past 140h it has run in my ownership...

d23haynes57 · 02-22-2025, 09:09 AM

Quote:

Originally Posted by mannebk

this is the one.

its runing strong at 203h total time. but oh my gosh, the smell i had to endure the past 140h it has run in my ownership...

I had that one in my 99 Tropi-Cal. Well, it is an overhead valve engine. You will want to check output voltage and frequency. The regulation is poor and mine was running under frequency which really strained the AC units and kept the battery charger from working properly. If you have an inverter/charger the off frequency can make it falsely go back to battery. Whenever I see those Generac home power commercials, I always think back to this POS. Mine would also go off on low oil pressure. Went to 15w-50 oil and added an oil cooler. And who thought putting this thing under the bedroom was a good idea? BTW the generator is a belt drive. After all these years you may want to check it.
This choice and install were not one of National RVs better moments.

mannebk · 02-22-2025, 01:21 PM

i concur on all accounts.

i had issues getting it started due to low oil pressure last year, new oil 15w40 and it starts good now. well see when it gets warmer.

belt is already in the spare parts locker.

i have issues with co inside the rv from that machine... 2h of runtime around 60% of load and i see 40ppm, already dangerous. nothing you want to keep yourself around for days and drive after that...