NAA

[Slack]

What could be the cause for the governor to constantly speed up and slow the engine? The tractor is a NAA from the 50's - gas engine

 

[Bob]

MOST likely, dirt/crud/ware/clogged passages/restricted fuel flow in the carburetor.

 

[agman48]

My Jub was doing that when using a blade, pulling hard then raising blade etc over and over. I reduced idle speed on the carb and shorted gov/carb linkage by 1/4" and it helped. Red Tiger engines seems to do that when going from loaded to nothing but reducing throttle will stop it until you go again. The gov was designed to work best under full continuious load like plowing where it works great, almost feels like a torque converter.
Anyway, you can always set things back where they were if no improvement.

 

[Blackhole49]

I agree with Bob. Most surging problems are carb not governor related.

 

[EJ70]

Same here. When transitioning from down hill to flat then up hill again pulling hay wagons with my 630. Same engine.