Carb adaptation

[MH81]

I have a love hate for Onan engines.
The Roper has an Onan.
I recently learned that Onan is from the Latin 'Oh Man' (or 'Oh Damn') and roughly translates to either "D!cked up Carburetor" or "Athsmatic Wonder". I am not a fan of their carbs or their intakes.
Anyways, I have put every kit in this POS and I've even changed the carb to one that was rebuilt by a mechanic. Same crap.
I am under strict orders to not drop another dime into this carb... So I bought another one. The wrong one. Oops
This one is for the other intake style. I need this tractor as soon as the weather breaks, so it was time to make an adapter.

New Carb

Intake

Paper template

1/4" copper plate

Assembled
(While it was off, I split the intake and resealed it. Dumba$$ idea to make them that way, but whatever.

And done.

The air cleaner will be modified to work or a different one put on and then the friggin thing may work when I try it next time. Grrr.

 

[Cat385B]

My local small engine shop has a really old tin Onan sign.

Cut and bent into a really neat ashtray.

 

[MH81]

My local small engine shop has a really old tin Onan sign.

Cut and bent into a really neat ashtray.

if it has been Nikki carburetors, I'd suggest they used it to hold their toilet brush.

 

[KennyP]

The carb on my B48G is not that good either. Runs great one time, floods the next!

 

[Lily'sDad]

MH, what were your symptoms with the old carb? It is hard to believe that the engine had troubles when new.

 

[olcowhand]

Alan, if you'd have mentioned this earlier, I have an adapter plate in my tool box I made years ago. I would have shipped it to you for free.

 

[olcowhand]

The old DD Marvel Schrieber carbs would never hold an adjustment. The jet screws stayed where you put them, but required constant adjusting as those carbs were a real pain.

 

[MNGB]

The old DD Marvel Schrieber carbs would never hold an adjustment. The jet screws stayed where you put them, but required constant adjusting as those carbs were a real pain.

Yes the MS was is a POS carb I had a Suburban SS16 and it was a constant fight with the carb my fix was to remove the Onan and install a nice running B&S V twin 16 hp fun to operate now

 

[MH81]

MH, what were your symptoms with the old carb? It is hard to believe that the engine had troubles when new.

I'm sure it's the guy working on it, but I normally can get a carb right by the 6th or 7th time.
This time, it would stall at very inconvenient times (stuff on the loader, half over a tailgate, half over the air) and to require random choke amounts.

Also, it has an electric fuel pump, and a brass float.

We will see howlong this solution works.

 

[Lily'sDad]

Do you suppose the float was set too high allowing excess fuel to slop over?

 

[MH81]

Do you suppose the float was set too high allowing excess fuel to slop over?

I don't know.
One time it's flooding, next time starving. As my dad used to say "It's enough to Piss off the Pope"

 

[MNGB]

MH81 I'm thinking you will like that Nikki carb I really disliked Onan's after my experience with one in the Suburban but this summer I bought a Case 446 it has the Nikki carb and the Onan in the Case runs really nice it starts and just runs nice (never thought I'd say that)

 

[dodge trucker]

Well being as how you said you tried another carb (even though rebuilt by someone else) would it still be the carb if it ran the same with both? What about that intake that you had apart and resealed? Could it have pinhole(s) in it? I have heard of issues with the intake manifolds on some Kohler opposed twins, that were a 2 pc design, that intake looks to be made the same way as the troublesome Kohler ones.

 

[MH81]

Well being as how you said you tried another carb (even though rebuilt by someone else) would it still be the carb if it ran the same with both? What about that intake that you had apart and resealed? Could it have pinhole(s) in it? I have heard of issues with the intake manifolds on some Kohler opposed twins, that were a 2 pc design, that intake looks to be made the same way as the troublesome Kohler ones.

I'm not sure where.the issues lay. The carb I swapped had a manifold on it.
But they both might have had air leaks. I didn't take any chances with this one, I put it back together with fresh sealant and aluminum pop rivets.

 

[MH81]

I bought a “filter” that would fit al the measurements for under the hood.
It was actually just a pre cleaner, in spite of the ads assurance it was a filter.
Anyways... I put a piece of filter foam in, a piece of SS hardware cloth on top of the carb so the engine doesn’t suck in my foam a second time, and put the breather back to the carb.

Last item is a choke cable bracket. May get that done today.

 

[KennyP]

Ain't that cute!

 

[Cat385B]

I think there’s a doohicky on his whattadoyacallit.