Low power and stalls when mowing

[lehubbard]

I have a 1950 farmall cub. It seems like I have low power. I have been trying to mow, but the tractor stalls out when I engage the pto. The tractor seems to run fine otherwise. If the drive belt isn't attached, the tractor runs fine with the pto engaged. When I rev the throttle up all the way, there are about three notches that the lever wont reach. I have tries adjusting the governor linkage according to the manual, but that didn't seem to help. At one point, the linkage fell off the carburetor while the tractor was running, and the engine started running way faster than it does at full throttle. Is the tractor supposed to be able to run that fast?

[Eugene]

At one point, the linkage fell off the carburetor while the tractor was running, and the engine started running way faster than it does at full throttle. Is the tractor supposed to be able to run that fast?

Yes, it will run quite fast, guessing 5K RPM.

Low power. Complete engine tune up starting with compression tests.

[tst]

due to design yes a few teeth are unused, check all the spindles and idler pulleys to make sure they are good, spin freely
yes check compression, points, timing

[Glen]

At one point, the linkage fell off the carburetor while the tractor was running, and the engine started running way faster than it does at full throttle. Is the tractor supposed to be able to run that fast?

Hi,
It can run faster than 1800 RPM if the throttle valve in the carburetor goes fully open.
It should not go open to more than 1800 RPM sitting and running.
The valve is partially open to run at 1800 RPM.
Don't let the engine run as fast as you said. Stop it if it tries to run overly fast, and find the problem.
Be sure the pin in the yoke, and cotter keys are in place at the ends of the rod ahead of the carburetor.

[inairam]

What type of mower deck do you have? How high is the grass? If the mower deck has 3 spindles it is a finish mower deck and high grass will put a lot of load on the cub.

You adjust the linkage between the governor and the carb per the manual to get "full throttle". The notches on the throttle lever do not really mean much. Most of my cubs do not use the last couple of notches.

[lehubbard]

The mower is a danco c-1 finish mower. The tractor stalls even in short grass. The spindles also spin freely.

[Urbish]

The Danco C-1 is at the upper end of what a Cub will power. In order to run a deck of that size, all systems on the tractor and on the mower have to be finely tuned. Here are a few things you can check on the mower side:

Park the tractor on a flat, level surface. Manually turn your blades so they are oriented inline with the centerline of the tractor. Measure from the front and back of the blades to the ground at your desired mowing height. You want the front of the blade to be slightly lower to avoid double-cutting your grass, effectively doubling the power required to run the deck.

Check the idler pulleys on the belt drive to ensure that they turn freely. A roached pulley bearing can add a lot of load to the system.

Keep those blades SHARP. Dull blades take more power to turn.

Check your belt tension. The belt should be tight enough so that it doesn't slip or flop around when running. An over-tightened belt will be harder to turn.

On the tractor side, you will want to ensure that you have adequate compression, properly firing ignition system, and timing set appropriately.