Farmall H M Governor

A few years ago my Dad aquired an M that had been used a lot but taken very good care of. The Governor was completely wore out. I had an H engine that I bought that had the original cast iron psitons in it and the original governor hanging on the side. I was pretty tight yet. We changed the gear. We had enough parts around to change the top with very tight parts. The tractor is running stock 1600 high idle RPMs. We put it on the dyno and it has 55hp at 540 pto. When we pull it down to 500 pto it only goes up to 56hp. I have never seen a Farmall hit max hp at 540 PTO. As far as I can tell the M & H governor weights are identical. I have never seen a factory governor perform this well. This caused me to go Hmmmmm. Are the factory Governors that good when they are new? Is the difference in the spring? I am attempting to understand these governors better so any help is greatly appreciated.

An M governor that is in good shape should do just that. Starting at 1595 high idle rpm should have throttle plate in carb full open just before you hit 1450rpm. Torque rise after that point will depend on what is in the engine for pistons etc. Remember, when reading the dyno that is set to read horse power at 540 rpm that any reading above that rpm is actually reading low and any reading below 540 the horse power is actually less that what it is showing unless the torque rise is sufficient to equal the loss of rpm. That usually takes over 25 percent torque rise to maintain horse power at lower rpms. I used to rebuild many , many governors when dyno testing as that was the number one cause of loss of horse power. The engine still had the pulling power(torque) but it occured at a much lower rpm therefore lacked the snap to get in there and dig before it dropped out.

Much appreciated!

Pete, where does one get a governor rebuilt? any suggestions?

Because of my experience with a very tight governor on my Dad's Farmall M I started looking into what it would take to re-build one. To buy the parts from Case-IH seemed unreasonable so I have bought all materials I need to rebuild one from McMaster Carr. What I do for the weights is machine them out to 5/16" and press in a brass bushing. Then I fit them to a .002" oversized pin same as fitting a wrist pin. Machining out the weights can be tricky because the holes in the weights wear in one direction and center of the machined holes needs to be on the center of the original hole. For the linkage I make pins out of 9/32" brass rod. I made a jig that allows me to drill 1/16" holes in the brass rod precisely where they need to be to replace the 1/4" clevis pins. Then I drill out the linkage and fit them same as fitting a wrist pin. I replace the 1/4" throttle shaft bushing with a longer one so that if the throttle shaft is worn a little it is using a new unused portion of the throttle shaft. If the input shaft into the governor is wore I have 1/2 x 5/8 bushings that I can use to re-bush the housing and then if the shaft is wore I can build it up with brass and turn it down in the lathe. I replace the seal with a new one. So far I have only done a few of them but they really turn out great and the cost for parts stays below 20 dollars from McMaster Carr. I even figured out which gasket material to buy from McMaster to make new gaskets. So the cost to re-build one this way is mostly labor. To do one this precisely does require a mill, lathe, hand reamers, sunnen hone, and a high level of mechanical ability. At first my intention was to just see if I could rebuild them. Turns out I can do a better job than I thought. I just did one last weekend for my Dad's 450 that turned out beautiful. I started looking into what places like Denny’s want for one re-built to factory specs and I thought maybe I should rebuild these for other people. Next one I rebuild I am going to take pictures of the process to have to show people exactly how they turn out. Email me if you are interested. FYI – I undercharge compared to other people.

Actually the factory governors were very poor, in our area you almost cant find an H,M or SM that doesn't have an M&W governor.

With the price of governor weights and carriers being out of this world here is what I do. I drill the weights and carrier out so a roll pin will fit tight in carrier and free in weights. Did my own two H's and one M and I feel the governors are plenty active. If bushings, needle bearings and thrust bearings are worn of course you will need new ones. Do not substitute a will fit for the ball thrust bearing though as it is a special bearing to smoothly handle the thrust of the weights. I used to repair many governors when the kits were like 50 to 80 dollars but the last one I did with an IH kit cost over $400 and that was over twenty years ago.

The one hole in the weights always wears into a slot. The challenge with drilling out a slotted hole is the center of the new hole is not the center of the old hole. Properly alligning them in a mill vise and using a mill end places the center of the new hole precisely on center of the old hole. If what you do works good enough for you then go with it. My standards can be summed up with two questions. Is it done as accurately as possible? Is it as precise as I can get it?

Oh, I am sure they are not 100 percent but actually I was pleasantly surprised how well they do work out. If both weights contact the thrust washer equally and move smoothly you have the battle mostly won. I have no need to put them on a dyno to test them as they are only dink around tractors now days but I am very happy with the way they respond to change in loads like going up the hills etc.