Farmall M High throttle

I have a 1941 Farmall M. so my problem is when i throttle up all the way it just doesnt seem very high for this tractor. i would think it would go much higher than what its going. my brother has an A and it has more rpm at high throttle. anywho i rebuilt the carb and got that adjusted pretty good. just cant seem to get the high speed up. could it be governor adjustment? thanks for your help.

It should be about the same RPM as the other tractor. To determine if the linkage to the governor is worn, do the following: Engine off. With the throttle lever far
forward (idle), stand on the left side of the tractor and look at the governor. (in front of the carburetor) between its housing and the engine block is a curved
lever connected to a linkage rod (part #22). This lever is now in the idle position. Disconnect the linkage from the arm. Now pull the throttle hand lever up at the
steering wheel to highest speed position, full back toward the steering wheel. Once again at the governor, move the curved lever to its maximum travel (it is against
a spring, but should be OK to do by hand. This is the governors full speed position. now test the position of the linkage rod to see if it is actually pulling the
curved lever to that maximum position. If it does not, that is the first thing to fix. (many wear enough to cause slow engine speed at full throttle).
The governor lever you are adjusting cannot cause the engine to overspeed. That curved arm must move to full stop position with the hand lever motion.
There is a linkage pivot at the top of the engine above the carburetor (parts 11 and 12). It has a bent metal bracket and a double ended lever (see diagram in link)
there are also two springs and threads on the rod coming from the hand lever. these springs are often rusted/broken/collapsed. They can be replaced with springs from
a hard ware store, they are important, but not critical. The linkage can be adjusted there (with new springs if needed) so the rod assembly moves the governor arm
through full travel. On Farmalls the first 1/3 of the hand lever travel often does nothing, so that would be normal after adjustment/repair. The diagram does not
show the upper rod and spring bracket (other parts diagrams would, but they won't help as much as looking at the real thing. Lifting the hood (muffler off) will ease
access dramatically. Be assured, the adjustment will not cause excess engine speed. Jim
Parts diagram.

oh ok that makes sense, thank you so much

Your A should run around 1600 rpm, where the M will turn around 1300- 1400 rpm. There will be a difference....

The RPM is stamped on serial number plate, 1595. Make sure arm
on gov is firmly down against internal stop when throttle is all
the way to rear . Make necessary adjustments or repairs to
achieve that.

If still slow suspect weak gov internal spring or someone miss
adjusted the stop bolt.

My 1940 M had the same issue. I had to replace that spring in the governor, but then also had to adjust the stop screw inside the governor. I determined the correct RPM by using a hand held tachometer on the PTO shaft. Set it for 560 RPM. wide open throttle, no load.

The pto rpm on the M at 1595 engine rpm is 590. Had many on the
dyno years ago.