Governor Help

feg7846

Active member
Thanks to all of my fellow Cubers. This forum is SO informative and has helped me so much.

I have adquired a 1947 cub that sat out in the weather for a few years. Got it rewired, motor was not stuck, so I adjusted valves, primed oil pump, changed and adjusted points, new rotor button and got it running. Runs good with one exception. I had quite a problem trying to get the slow idle set. I have it set now but the carb idle adjust screw is screwed in all the way and tight on the spring. Idles great, but when I try and speed it up with the hand lever, it pops and shuts off. As part of my clean up on the cub, I took the governor apart and cleaned it up. But, I also removed the 2 lock set screws on the outside of the governor, one on top and one coming in from front. Don't know how to set them back, and, I think that may be where my problem is coming from. Can someone out there that knows a lot about governor settings give me a general idea on where these screws should be set. I know it depends a lot on wear and tear. Also my spring on lever on governor seems to be just fine and there are no wear groves on the lever. I have read the governor section of the manual, but just get somewhat confused. I know the setting will be different on every cub, but what I am looking for is a general idea of how many threads are showing on the outside of the screws, or, a measurement in inches, or other setting that you may recommend. I know this is probably a dumb question, but, hey, I am 75 years old and a dumb question is allowed once in a while
Love my cub. I have never worked on a project that I have enjoyed as much as my cub. Have a good bit of implements also and plan on putting it all to work in preparation for spring garden. Thank all of you SO very much
 
The pop and shut off is probably not related to the governor. That sounds like air/fuel. I'd be looking at the fuel system (carburetor in particular) first.

You won't be able to properly adjust the governor until it runs well. The front screw damps surging and the top screw sets the high idle limit.
 
Hi,
The adjustment screw on the front of the governor is for helping to stop the engine speed from going up and down on it's own. There is usually not any problem with that, if the rod in front of the carburetor is adjusted right.
The Cub service manual says to not screw it in too far, it can interfere with the slow idle speed.

The adjustment on top of the governor is the high speed limit bolt.
It stops the throttle lever from going ahead too far.
A 1947 Cub should go 1800 RPM at full speed.

An automotive test tachometer can be used to set the speed, if the Cub has a Battery Ignition unit.
It won't work with a magneto, I guess.

Below are pics from TM Tractor.
The 1st pic is a governor case showing approximately where the adjustments are set.

The 2nd pic shows the high speed adjustment bolt, this is the original length. If the bolt has been replaced with another length, then the amount it is sticking up above the lock nut in the 1st pic might not be right.

The 3rd pic shows the idle speed adjustment screw, it is at the top area of the carburetor, it is the screw with the spring on it. It is on the engine side of the carburetor.
Move the throttle lever fully to the rear and adjust the screw so the engine runs at about 500 RPM.
The Cub operator's manual says the slow idle speed is 500 RPM. :)
 

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feg7846":3j4fbpxx said:
....... I had quite a problem trying to get the slow idle set. I have it set now but the carb idle adjust screw is screwed in all the way and tight on the spring. Idles great, but when I try and speed it up with the hand lever, it pops and shuts off. .......
The screw/spring that you are describing is not an idle adjustment, rather it's for air adjustment. Usually about 1 1/2 turns open from fully closed is a good setting for beginning the adjustment. The idle adjustment is a set screw that contacts a stop on the linkage. Also check/adjust the linkage to the governor when you remove the carb. Stan :hattip:
 
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