Farmall M

[bgretencord]

I have a Farmall M that has never run correctly without being partially choked. I have tried 2 separate carburetors and cleaned both, always runs the same. After further inspection, I found a poor patch on the intake side of the manifold, with what looks like JB Weld. I pulled the manifold off of the tractor and the patch fell right off, revealing a 1/2 diameter hole. I replaced the manifold with one I bought off of Ebay. Now when I start it, will not run at all without being choked. And when it is choked, the motor takes off like it is over revving. It appears that the governor shaft is connecting in the carburetor and working correctly. Any ideas where else to look? The manifold I purchased was marked 450, but from what I'm reading, it is the same manifold from the M through the 450. Sorry for the long post, just wanted to get all of the information out there. Thanks!

 

[Janicholson]

The tab and slot connector to the throttle shaft takes a very good light, and reading glasses and maybe dental picks to get it in correctly. The manifold may still have a mismatch at the head. the exhaust to intake surface needs to be tightened just to snug, then the manifold tightened to the head, then the two tightened. Jim

 

[used red MN]

I am going to pick on your wording, you say .. It appears that the governor shaft is connecting in the carburetor and working correctly. .. The connection between the governor shaft and the carb throttle shaft HAS TO BE CORRECT it cannot just appear to be correct. I have attached a link to the governor rod sold by YT. The single tang on the carb end ..left in photo.. engages in the notch between the two knobs that form a V on the carb throttle shaft connecting part. As Jim said a good light and if you need them your close work glasses are helpful to make sure this is right. Secondly, did you remove the throttle plate from the shaft when you cleaned your carbs? If so they have to be installed correctly so the plate closes correctly allow the throttle connection on the throttle shaft to rest against the idle stop screw. The throttle plate must also be centered in the carb throat correctly. This is accomplished by installing the plate with the screws leaving the screws loose to where the throttle plate will just move slightly. Now with the idle stop screw backed out to not interfere hold the throttle shaft to the closed position with your finger. Now tap the throttle plate lightly 3 or 4 times with your screwdriver blade so it seats in the center of the carb throat. Continue to hold it in that position and tighten the throttle plate screws. I actually think once you get the governor rod engaged with the throttle shaft properly it will run correctly.
YT governor shaft

 

[bgretencord]

Thank you for your tips. I'll try this the first chance I get. Hopefully the kids behave enough that Mom let's me outside to tinker. I agree, I was thinking governor too, but never had a problem prior to this that it made me think I was missing something else.

 

[bgretencord]

Thank you, I was thinking the governor. But I've never had any problems before with this and wanted to make sure that I didn't miss something else.

 

[bgretencord]

Good Evening, I had a chance to try to reset the tab from the governor shaft in the carburetor. On a whim I measured the tab, it is .35 off the face of the governor shaft tube. I then measured the U that the tab set in inside the carburetor, it is closer to .375. It looks like the tab is not engaging at all. I even pulled the governor shaft off the tractor and hooked it up to spare carburetor where I could see what the carb was doing. I spun the shaft 360 degrees and the butterfly never moved. So, I believe that the tab is not engaging. Does this sound plausible? Or am I crazy? No idea why I never had an problems before. I'm going to do more research on my own, but wanted to get my findings to you guys. Thanks, Blaine.

 

[bgretencord]

I should have added, that this is an M&W governor shaft.

 

[used red MN]

Sorry, I was watching a movie last night and did not check your post. I get this punishment for using Classic view occasionally. I do not know all the specialties of the M&W governor parts. The shaft should have a bushing type stop or shoulder welded on it as shown on the YT part. That bushing should give the shaft a positive stop when it is installed in the aluminum tube. So that means when it is installed on the tractor that keeps it from going more forward. So when installed in the tube the shaft should be positioned in relation to the carb for the inner hole to pilot over the carb throttle plate shaft. At that position it should also engage the tang into slot on the carb shaft. If it does not there is a possibility you have a shaft for an H instead of an M. I think the H shaft is shorter, it is a different part number. Have you had all of this assembled and working before or are you changing to this governor?

As for M&W or Rocket governors I have never been a big believer in them for there extra cost. All they do is increase throttle response ever so slightly and give you a seat of the pants feeling that your tractor has more power. As far as tractor pulling or what ever when the engine pulls down an IH governor will open the throttle plate wide open same as an M&W, you cannot get anything to give you more power than that position.

 

[bgretencord]

That really makes me wonder if I have the correct shaft. This tractor seems to be one minor headache after another. I believe the previous owner patched several different things just to move it down the road, now I'm finding them one at time. He claimed to run it at tractor pulls, which could explain a lot about my problems, But, to answer your question, yes it was previously connected and working. I am speculating that it engaged just enough to work and now I'm having trouble with it. I am going to order the shaft that you recommended here shortly. Hopefully have it by the weekend so I can try it out. Get this question answered once and for all. Thank you!

 

[used red MN]

Well now you are calling me on the carpet, buying a $40 part. I know the H and M use the same governor internals and case with the ..D.. shaped lid. The engine of the H is shorter than the one in the M. So that distance from the carb which mounts nearly in the center of the engine to the part that mounts above the governor case ..19.. in diagram has to be made up somewhere.
CNHI Farmall M governor

 

[bgretencord]

Not at all, I appreciate the advice! I've tried so much getting this to run right, that I'm down to throwing parts at it! Hard to say how much this thing has been tinkered with in it's 74 year life.

 

[bgretencord]

So I got the new governor shaft and compared it to the old shaft over the weekend. All dimensions are the same. I think my next step is to compare the original manifold with the manifold that I purchased, since changing this is where my problem started. Thank you for all of your help, I'll post again once I figured out the true problem. Maybe this can help someone else in the future.

 

[bgretencord]

All, just wanted to follow up with what I found over the past few months. The governor shaft was good, turns out you need to put everything back together correctly. I then checked the original manifold and found a crack. Had a friend repair it and he kept finding more cracks, which he repaired. I feel confident in the repairs. Found wiring issues next, have a wiring harness coming tomorrow. Repair that and hopefully have a good running tractor. I apologize for my delay in relaying all of this information. Sometimes life gets in the way and I can go weeks in between working on this. Thank you all for your help!

Blaine

 

[used red MN]

Glad you got it figured out, thanks for letting us know!