Dumb Question # 412

biggerred · Jun 4, 2011

I haven't taken it down yet, so I'm asking beforehand: will the carb off an M Farmall fit a 300 farmall. They sure look the same, and No I dont have a parts manual. (I thought I'd answer that first as someone always assumes we small time guys have stacks of manuals laying around LOL)

CharlieNJ · Jun 4, 2011

Go to Case IH website, parts manuals for both tractors are there, complete with part mumbers and exploded views, for the small timers.

Anonymous-0 · Jun 4, 2011

I thought an M & 400 would interchange. The H & 300 would interchange.

CNKS · Jun 5, 2011

It will "fit" if the bolt pattern to fit the manifold is the same, which I think it is. Max power on the 300 carb is with the main jet screw 5 turns out. Main jet adjustment on the M carb is in until rough, out until smooth. In other words the internal parts "may" be different, however you may or may not notice the difference in the way it runs. As to the manual, go to www.caseih.com and look the carbs up. I am a "small time guy" and the first thing I buy for a tractor is the manuals. There is a LOT even in the Operators manual that you need to know, and you are unlikely to get the fine details on this forum unless you ask very specific questions. You need to read the thing.

CNKS · Jun 5, 2011

300, Super H have a manifold with different hole spacing than the H. I think replacement manifolds fit either.

biggerred · Jun 5, 2011

it was a joke, thus the LOL

biggerred · Jun 5, 2011

good info, thanks

Nebraska Cowman · Jun 5, 2011

BUT... what people forget is that the carburetor may have been changed 40 years ago for one that "looked" like it would fit. OR an M carb could have been overhauled with H jets and venturi or vice versa. We have no way to know unless to had the specs and used wire gauges to check it all out. Farmall F20 and F30 carbs look the same too and get interchanged. And I've seen more than one 10-20 carb changed with a Farmall Regular.

CNKS · Jun 5, 2011

The only way to know is to check the part number on the carb, which requiers a manual (or at least the CIH web site), which the newer people don't seem to like to purchase. As you say, even then, what is inside the carb is anyones guess. But, usually it is not a problem.

mkirsch · Jun 6, 2011

(quoted from post at 08:46:58 06/05/11) it was a joke, thus the LOL

I dunno. I guess I failed to find the humor in it... These days manuals are cheap and readily available, so unless you have it all in your head it's really penny wise and pound foolish not to get a set.

BTW, the original H's carburetor was completely different. When IH brought out the Super H, they used the same carburetor body as what was on the M. That continued through the 300 and 350.

I have got to imagine that since the 300 is putting out as much power as an original M, that the venturi and jetting of the two carburetors is going to be about the same. After all, it takes a certain amount of air and fuel to make a certain amount of horsepower.

rustyfarmall · Jun 6, 2011

(quoted from post at 19:11:41 06/04/11) I haven't taken it down yet, so I'm asking beforehand: will the carb off an M Farmall fit a 300 farmall. They sure look the same, and No I dont have a parts manual. (I thought I'd answer that first as someone always assumes we small time guys have stacks of manuals laying around LOL)

It will physically bolt up. The fuel line will fit and the governor tube will fit, BUT, the choke lever will be on the OUTSIDE of the M carb, and the 300 has the choke lever on the INSIDE. That little issue CAN be worked around if you need to.

Dumb Question # 412

biggerred

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CharlieNJ

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Anonymous-0

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CNKS

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CNKS

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biggerred

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biggerred

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Nebraska Cowman

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CNKS

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mkirsch

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rustyfarmall

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