Help with carb on old Onan-Montgomery gas engine

[Quebecnewf]

As some of you know I received an old gas engine with the old planer I rebuilt this summer. While I have repowered the planer with a new engine I am looking to get the old engine running as well.

Here is what I know . The engine is a 10 hp Onan-Montgomery gas engine. Made in Brazil . Looks almost exactly like a model 23 Briggs .

I have had it running but the carb is shot. Might get by with a rebuild kit but I am thinking not. Parts missing, jet seat corrosion etc etc.

Been trying to identify the carb over on the Smokstak old engine site . Some information but still no way forward.
I am thinking I am not going to find a replacement carb of the exact same type so I need to come up with a aftermarket carb .

I am posting a few pics of engine and carb . Maybe someone here has the info I need

Quebecnewf

Old engine

Carb

Another view of carb mounted on engine

Another view of carb removed

[Kbeitz]

Here in the states a 10 hp Onan is rare. I have only see a few on Gravely tractors.

 

[Quebecnewf]

Motor is called a Montgomery. The small tag on the side says Onan - Montgomery.

Not looking good for getting it repaired. Something made in Brazil a long time ago is a hard fix.

Quebecnewf

[Kbeitz]

Found a little History on it...

https://www.smokstak.com/forum/showthread.php?t=125881

[Quebecnewf]

Yes I read that as well and watched the video . Same as my engine .

Quebecnewf

[Kbeitz]

What I would do to take a small chunk of pipe and weld two washers
on the ends. Drill one end to fit your engine and the other side to fit
what ever carb you can buy. Carb adapter.



 

[dustyhat]

Dont know your style but thinking a Zenith would fit from a Wisconsin. that might even be a zenith type.

[sawguy21]

I am thinking the same thing.

[Slingshot]

Looks similar to the carb on a International-Farmall Cub tractor.
Here are some pictures and a rule for measurements......



 



 



 



 



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[WLC]

Might try here:  https://www.smallenginesuppliers.com/  May take some searching to try and find a fit.  Your carb looks a lot like the one off my old, Troybilt tiller with the 8hp Briggs on it.

[Slingshot]

Here is a picture of the Cub carb with a carb gasket sitting on it from a
9hp Onan engine on a generator from a 1973 Winnebago motorhome.
The bolt pattern is the same. The carb on my Onan (which needs replacing)
has horizontal draft rather than up draft or I would try it.
The older Cub tractors have a 4 cylinder 12hp engine.



 



 


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[Don P]

Wow, I have what looks like exactly that generator from a '72 motorhome, 4kw IIRC. And it needs a carb at some point. Holler if you find them at a good price.

[pineywoods]

Looks just like the carb on my old (60's) massey ferguson tractor. Jet would probably be different, but it's removable. 4 cyl continental engine.

[richhiway]

I would think you could rebuild the carb you have.  Not much to them, just clean it up and should work fine. Go easy on the bowl gasket when you take it apart so you can reuse it or use as a pattern to cut a new one.

[Chuck White]

Hey Slingshot, I have a generator just like that out in my shed!

Runs at 1800 rpm's.

Mine needs a new or refurbished or salvage yard distributor!

Haven't had it running in a lot of years, I just go out once in a while and turn the motor over by hand!

[Slingshot]

Chuck White,
Mine hasn't run for over15 years. Also runs at 1800 rpm. We would
run it in the Winnebago on the road to run the roof air conditioner, (no air on the engine.)
Sort of a pleasant rumble. Nothing like the screaming sound of the high rpm generators.
Engine still turns freely. Didn't take care of it so carb is so full of varnish it won't clean up.





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[starmac]

Carb is so full of varnish, it won't clean up? How is that possible, I would think soaking it in a vat of carb cleaner would take away everything but the metal. I know if it is a metal carb, you can vat it in the old caustic vats, and even any aluminum or brass will dissolve, nothing but clean metal left.

[sawguy21]

Don't hot tank a carburetor. any aluminum or brass will be ruined. Maybe a local saw shop would be willing to run it through an ultrasonic cleaner

[Quebecnewf]

All good replies guys . Thanks for the pics as well. I am thinking as i poke around a bit more that I am going to go the replacement route. While i am quite sure this is an old version of some of the carbs pictured ( it looks quite similar to some ) I have yet to find an exact match.

My concern is the linkage to the governer . How fussy a thing is this . .? . I only know enough about carbs to mostly fool them up .

Going to the big city of Montreal next week . Will take old carb with me and go looking for some small engine repair shops Craig's list , kijiji etc etc .

Any ideas or shops in that area ??

Quebecnewf

[roger 4400]

Paul I will try to find some tomorrow. In Mtl or near my house.
It is for an Onan -Montgomery 10 hp. .....be back to you. Roger

[roger 4400]

Hi Paul. Called some specialized in small engine fix shops, they refer me to the Onan distributor in our region ......he never heard of your carb ( gave him the carb numbers...) he called Onan company and distributor....they are not aware of this carb......but they say it may be replace with a small tractor carb, Zenith or other if they have the same seat. Sorry I tried. Roger