Super M surging / hunting

I have a 1952 Super M.

Has surging or hunting at idle, half throttle. Runs perfectly under load at 3/4 to full throttle ( really any throttle position under a load ).

Tractor has ran perfect for years and has just starting doing this. Tappets checked for proper adjustment. Has brand new carburetor, coil, points, plugs and distributor ( timing also checked ). Surging / hunting was happening prior to new parts, none of these have helped the issue.

Nothing has ever been done to governor

Thoughts

Why all the new parts?? One should never put on new parts till they have done there trouble shooting or you add to the problem.
So does choking it a bit help or hurt?? A new carb need to be adjusted to the gov. as per the I-T manual and it is about a page long as to how to do it. Adjust the carb to the gov. and then post back if the problem stays or goes

and none of the new parts are the cause of surging. its the governor adjustment ,or problem.

Surging is usually caused from a lean mixture.

Try a partial choke to see if it will level out. If it does, it is too lean. Be sure there are no vacuum leaks.

Try adjusting the idle mixture. It must be adjusted with the engine at a low idle speed, and up to operating temperature.

The throttle should be held firmly against the idle stop screw when the dash lever is in the idle position. If not the linkage may need adjusting.

Doesn't that happen sometimes when the bushings are wore out around the throttle shaft? Lets it suck air in there.

Holding the linkage still between the governor and the carb will tell you where your trouble lies. Refer to the attached diagram, if it is fuzzy click it and it will display as a clearer picture. Take the 2 screws out of the breather 3 that attach it to 19. Turn the slanted cover forward, but make sure it clears the fan. Under the cover is the linkage 7 coming up out of the governor and on the upper end part 6 connects to 14. Start up the tractor and run it at a speed that it surges. Being careful of the fan steady that linkage with your fingers. When you have it steady if it still surges the problem is the carb, if it runs steady the governor is the issue, which is my bet.
See diagram

This happened on my H so I replaced the top half with a tight throttle shaft. problem cured.

Surging on them can come from a couple places. (1) running the carb main fuel adjustment to lean , so set between 4 and 1/2 to five turns off the seat , Next not having the carb to gov. in sync . Like said below remove the breather with ENGINE OFF pull the throttle wide open , then remove the small headed pin on the clevis hooking the gov rod to the carb linkage and then try and move the carb linkage to see if it will move feather open if so loosen the jam nut and adjust the clevis so that the pin will slide in freely . NOW what i do is i add one half turn more and install the pin and set the jam nut. Next on the list is missing bushing in the two arms inside the gov . where the spring goes , Yes the arms had Bushing at one time MANY have fallen out and allow the spring to fit vary loosely . No you can not buy of find them so i make them out of bearing bronze and press fit them . Due to the curve on the spring hook you have chamfer and the hole for the spring to fit in is a little lager then the wire dia. Yea i know i should have all the dementions wrote down and a detailed blue print so i could post . I make each to fit what i am working on .It is best to heat the ends of the arms up a bit they do not have to be cherry red to install the bushing . Do not try and force them as the cast ends will break as you olny want around .001 interference fit .

Thank you, I will try that and see if the governor is the issue.

If load setting to lean, wouldnt it lose power under load?

Thank you. Tractor never needs choked. Starts right up without any choke, summer or winter.

I will see if a partial choke helps it.

I was advised I had to much play in advance timing of distributor ( weights / springs ) worn. Replaced complete distributor as I could not find those parts.

Carb was replaced as I was again advised that upon a carburetor check / adjustment that the idle mixture needle was not working properly. I was not comfortable doing a rebuild of carb

Tappets checked due to my dads suggestion.

I will have to find the I-t manual for this carb / governor alignment procedure to verify

Thank you

Is it the IH-8 I&T manual?

YES paragraph 161 page 44

check manifold studs to see if tight. Some times you dont need gasket

Thank you

Always happy to help if and when I can