1963 Cub Engine RPM's

[Masmith]

I just bought a tractor back that I previously owned and know the history of recent maintenance. It runs very good but the engine RPM's seen low at full throttle. It has a 42 mower and cuts good, doesn't bog down, so I think the governor is working as it should. Before I start messing with adjustments I was hoping someone could possibly point me in the right direction. My thoughts are the throttle linkage is not adjusted properly? With the tractor running at full throttle, I can move the governor linkage back by hand and it revs up very nice.

[Masmith]

I saw this response in another posting. I will try to adjust the maximum speed stop screw.


The maximum engine speed is limited by a stop screw on the arm where the speed lever rod attaches to the governor. Once you hit the stop screw you cannot move the lever any farther forward.

[Don McCombs]

You might also lubricate all of the governor linkages and see if that produces any improvement.

[Eugene]

I would check the ignition timing and full throttle RPMs before I made any mechanical adjustments.

Timing light with tach.

[Glen]

Hi,
The full speed for a 1963 Cub is 2000 RPM.
I would use an automotive test tachometer to set the RPM.

You can set the low RPM when you use the tach also. It is 500 RPM.
A tach with a dial and pointer works better for a Cub, I think they have said on here.

Below is a pic from TM Tractor of the governor housing, showing the high speed adjustment bolt, at the top of the governor, it usually has to have the amount of bolt sticking up above the lock nut as in the pic.

The 2nd pic shows the linkage at the governor. Lube the pivot where the cotter key is with oil, they can get tight there from no lube.

[inairam]

It is almost never the governer itself. I would go over the linkage between the governor and the carb and adjustment on the carb 2 or 3 times before I would mess with the governor setting. You probably do want to replace the governor spring.

lube the linage connections, trim cotter pins to an appropriate length so they do not catch on something and cause a bind, adjust the linkage per the manual, adjust the carb per the manual.

[outdoors4evr]

I use a mechanical tachometer like this one on the PTO.
https://www.ebay.com/p/1833653069

Some timing lights also have an RPM readout.