Farmall 460 carburetor

Anonymous-0 · Nov 12, 2010

I recently replaced the exhaust manifold on a gas 460. During the repair, the tractor set for three months. All has been put back together and the engine fires up quickly with the choke pulled out. The engine will only run with the choke out and only run at 1800 rpm, no matter what position the throttle lever is in. If the choke is pushed in, the tractor immediately sputters and dies. The tractor was running ok before I replaced the exhaust manifold. What is causing this strange condition?

pete 23 · Nov 12, 2010

I would say you have intake manifold leaks as they do not align properly now with different exhaust manifold. You could spray something like w-d 40 or any penetrant where intake manifold fits to head and if engine changes speed or runs differently you have a leak. Most of the time on these old tractors you will need to surface the manifolds as a unit after they are bolted together. There is also a couple different gaskets used on these engines and a tightening procedure to be followed.

Charlie M · Nov 13, 2010

Sounds like one of your problems is the rod that comes from the governor back to the carburetor isn't attached correctly. That would cause the tractor to run wide open with no throttle control. I'd get that working first and then see what other problems you got.

CNKS · Nov 13, 2010

You seem to indicate that it is not your tractor, since you say "a 460". If not, then you need to ask the owner if it acted that way before you worked on it. My 460 ran wide open when I bought it--the governor needed new parts. However, the choke had nothing to do with it. As the other post said, check the linkage first. Also, if you replaced only the exhaust manifold, and tried to match an aftermarket manifold with the original IH intake part, they likely do not match, at least mine didn't. Check the fit of both manifolds and make sure the intake part fits tight along the entire length. If not, then the tractor usually won't start, but you might check anyway. The linkage or the governor itself is the likely problem, though.

Roger Reeves · Nov 13, 2010

(quoted from post at 13:48:29 11/13/10) You seem to indicate that it is not your tractor, since you say "a 460". If not, then you need to ask the owner if it acted that way before you worked on it. My 460 ran wide open when I bought it--the governor needed new parts. However, the choke had nothing to do with it. As the other post said, check the linkage first. Also, if you replaced only the exhaust manifold, and tried to match an aftermarket manifold with the original IH intake part, they likely do not match, at least mine didn't. Check the fit of both manifolds and make sure the intake part fits tight along the entire length. If not, then the tractor usually won't start, but you might check anyway. The linkage or the governor itself is the likely problem, though.

The 460 is my own that I bought in February. The tractor started and ran OK. The original exhaust manifold was rusted and the exhaust pipe to the muffler was in such bad shape, it could no longer support the muffler. I removed the exhaust and intake manifold as a unit and had a local ag mechanic remove and replace the exhaust manifold and mate it to the intake manifold. I then mounted the unit back on the tractor per his instructions. ( He has replaced many manifolds on Farmall tractors.) <br> I don't believe it is the governor because I disconnected the linkage to the throttle from the governor and the tractor still would only start with the choke all the way out and run at high RPM. The throttle itself remained in the idle position. The tractor would sputter and die the moment the choke was pushed in. Since the gas set in the carburetor for several months, could the carburetor be gummed up?

rustyfarmall · Nov 14, 2010

(quoted from post at 20:12:34 11/13/10)

(quoted from post at 13:48:29 11/13/10) You seem to indicate that it is not your tractor, since you say "a 460". If not, then you need to ask the owner if it acted that way before you worked on it. My 460 ran wide open when I bought it--the governor needed new parts. However, the choke had nothing to do with it. As the other post said, check the linkage first. Also, if you replaced only the exhaust manifold, and tried to match an aftermarket manifold with the original IH intake part, they likely do not match, at least mine didn't. Check the fit of both manifolds and make sure the intake part fits tight along the entire length. If not, then the tractor usually won't start, but you might check anyway. The linkage or the governor itself is the likely problem, though.

Click to expand...

The 460 is my own that I bought in February. The tractor started and ran OK. The original exhaust manifold was rusted and the exhaust pipe to the muffler was in such bad shape, it could no longer support the muffler. I removed the exhaust and intake manifold as a unit and had a local ag mechanic remove and replace the exhaust manifold and mate it to the intake manifold. I then mounted the unit back on the tractor per his instructions. ( He has replaced many manifolds on Farmall tractors.) <br> I don't believe it is the governor because I disconnected the linkage to the throttle from the governor and the tractor still would only start with the choke all the way out and run at high RPM. The throttle itself remained in the idle position. The tractor would sputter and die the moment the choke was pushed in. Since the gas set in the carburetor for several months, could the carburetor be gummed up?

It is simply amazing how folks on this board can come up with answers totally unrelated to the problem at hand. Yes, the carburetor is gummed up. You might be able to cure the problem by dis-connecting the fuel line where it goes into the carburetor and spraying generous amounts of aerosol carb cleaner into the carburetor, but most likely you need to take the carb apart and either repalce the needle valve and seat, or at least give those 2 items a good cleaning. If the carburetor is REALLY nasty looking inside, a complete and thorough cleaning and rebuild is in order.

CNKS · Nov 14, 2010

Yes the choke needing to be wide open is a red flag as far as the carb goes and does indicate that the carb needs to be cleaned. However, I have never seen a "gummed up" carb that caused the tractor to run wide open. I think there must be better gasoline in my area, as I have left gas in carbs for a year and have not had trouble starting them (I don't recommend that). I mentioned the governor because your wide open symptoms were the same as when I bought my 460, other than the choke.

pete 23 · Nov 14, 2010

It cannot run at high speed without air. You indicate the throttle on carb, disconnected , is still in idle position. So,if the butterfly is actually in low idle position you are getting air from someplace else, bypassing the carb, reason you have to choke it so much to create some suction at carb to get any fuel. I would take carb off and check throttle plate and if closing correctly, look for air leaks.

Roger Reeves · Dec 11, 2010

I tried spraying WD-40 around the manifold while the tractor was running ( choke out and high rpm). The WD-40 was sucked in. I took off both manifolds and sure enough, the new exhaust manifold was not in line with the original intake manifold. The exhaust manifold was at least a sixteenth of an inch proud of the intake manifold. I took both manifolds as a unit to a machine shop and had them planed so that they were perfectly aligned. Today, I put the manifolds back on the 460. With the choke out and the throttle nudged a bit past idle, the engine fired up after just a few revolutions and ran great! Thank you to those that responded to my problem on this forum: you saved the day!!!!

Farmall 460 carburetor

Anonymous-0

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pete 23

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Charlie M

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CNKS

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Roger Reeves

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rustyfarmall

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CNKS

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pete 23

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