John Deere B - Carb or governor?

[ndgregor]

The B is up and running now, but it is running rough. It will not hold a steady engine speed, slows down until the governor picks it up and repeats the process. It seems to do this regardless of throttle position, but is more pronounced at low throttle. I also did notice that when it is under load (I.e going up a hill, driving in the field in the snow) it seems to run more steady.

Would you suspect carb issues or something with the governor/governor linkage assembly? I did pull the carb apart and clean it, but just used air and brake clean. Any help would be very appreciated!

 

[PHPaul]

First suspect is the carb, and in the carb the first suspect is the idle circuit.

 

[Dave M7040]

ND

I dont know anything about your tractor but when I started searching I came across a wealth of information on yesterdays tractors on this link.

John Deere 3020 Zenith Carb Question - Yesterday's Tractors

If I am understanding which John Deere you have, the carbs had different versions. Some with an accelerator pump, some with a constant velocity diaphragm which would be destroyed whenever the engine backfired.

I am 70 so have been around engines a long time just not yours. Carb is my number one suspect and the brake clean and compressed air often, but not always, gets the stuff out of the tiny passages.

Are you aware of ultrasonic carb cleaners many small engine shops are using. It is the same technology jewelers have used for a long time to clean intricate pieces.

On carbs I tried the old techniques to clean and if the engine still was not running the best, I would take it to a local small engine shop to put it in their ultrasonic bath. The results were amazing.

This link shows you what they are about and the cost. An individual cannot justify spending that kind of money but a small engine business can. Ultrasonic Carburetor Cleaning Systems

The youtube video shows the process and results. Ultrasonic carb cleaning - YouTube

The governor is just reacting to the unstable engine rpm and trying to correct the problem caused by the carb.

Dave M7040