Super M will not lug at end of a tractor pull

[Doug Rosenbauer]

Have two super Ms. One has high dome pistons and 350 or 400 head. Other is completely stock. Stock SM pulls about 20-30 feet further than one with high dome pistons and diff head. The high dome SM boggs down and dies where stock S M lugs when weight gets heavy. It used to be the other way around with the high dome S M beating the stock S M by 10 feet or so. Been told governor or possibly in points. Both tractors are 12 volt and both have electronic ignition. Any thoughts as to reason and easiest/economical way to address this issue?

 

[Dieseltech]

Is ignition timing set the same on both engines? Is the distributor ADVANCE CURVE set the same? That can make a difference. The governor I doubt is the problem unless set completely wrong. Too MUCH low speed timing advance will hurt the engine lugging ability on any engine.

 

[teddy52food]

Have you checked compression & timing. If the timing is advanced too far it may be kicking back when the RPMs drop.

 

[rustred]

best is to follow the adjustment from the service manual. check your timing also and even a valve setting as thats an overlooked thing. plus this electronic ignition thing who knows. the old points and 6 volt pull good also is my experience.

 

[Doug Rosenbauer]

All the comments make sense. Does these suggestions still apply if governor doesn't seem to kick in at all? I am not real knowledgeable about engines so if dumb question, I apologize....lol.

 

[Janicholson]

Have two super Ms. One has high dome pistons and 350 or 400 head. Other is completely stock. Stock SM pulls about 20-30 feet further than one with high dome pistons and diff head. The high dome SM boggs down and dies where stock S M lugs when weight gets heavy. It used to be the other way around with the high dome S M beating the stock S M by 10 feet or so. Been told governor or possibly in points. Both tractors are 12 volt and both have electronic ignition. Any thoughts as to reason and easiest/economical way to address this issue?

Well it can't be a 350 head because that is a head for a "H" derived tractor. I think a timing issue is suspect. The advance for a higher compression SM should be about 20 degrees. that is less than a stock SM. And if the mechanism is broken, it makes it worse, in that it won't have enough advance. Jim

 

[used red MN]

Have two super Ms. One has high dome pistons and 350 or 400 head. Other is completely stock. Stock SM pulls about 20-30 feet further than one with high dome pistons and diff head. The high dome SM boggs down and dies where stock S M lugs when weight gets heavy. It used to be the other way around with the high dome S M beating the stock S M by 10 feet or so. Been told governor or possibly in points. Both tractors are 12 volt and both have electronic ignition. Any thoughts as to reason and easiest/economical way to address this issue?

Since you’re a puller there is probably a good chance you use those K & N air filters that will screw up your engine for sure if you use it in the field much. If you are running through the stock oil bath have you checked to see if the tube coming through it from above the hood is clear. Maybe try a (ONE) run with the carb intake open and see if that helps. The mesh filter media may need to be cleaned. And yes just making sure the spark advance is work would be a big one. Usually unless the governor is clapped out bad once the engine rpm drops 500 she’s got the throttle plate straight up and down. You can’t get more than that.
By the way on the 350 head you will have to call Johnny Cash to get that to fit an M. Because when you would try to fit them together all the holes would be gone! The 350 is a hopped up H, head is dimensionally quite a bit smaller.
About your first identical post you can edit all the wording out and just leave an “Oops” Not sure where the edit button is on a PC. On a phone you click the 3 dots at the bottom left. I think the edit is only allowed for an hour or something goofy like that. I don’t understand that limit, but that’s just me.

 

[Janicholson]

All the comments make sense. Does these suggestions still apply if governor doesn't seem to kick in at all? I am not real knowledgeable about engines so if dumb question, I apologize....lol.

The governor is working (at least it must be to a major degree, or the modified SM would fall on it face getting to the sled, let alone actually pulling. One other thought that could apply is a cam gear loose on its drive key. Has there been any repairs or changes needed on the affected tractor? Jim

 

[Brownie450]

Is the main jet open enough on the carb? Probably needs
opened a bit to feed more gas on a hard pull.
Jim

 

[560Dennis]

suggest getting bulletin 1 014 476 r2 cut out illustration one ,put one the damper pulley as as stated and time it .
this in section IV for tractors equipped with fire crater increased power package.

If proper advance can’t be achieved blue ribbon service manual gss-1052 page 63

 

[rustred]

Is the main jet open enough on the carb? Probably needs
opened a bit to feed more gas on a hard pull.
Jim

for pulling give it 5 turns out and your off the needle seat , and it is at maximum gas it can suck out. we never get any of this info and dont know a persons knowledge on stuff. if a person writes a book then the guy says i know that. screw the needle in till it stops then back it out counting the turns. the bottom screw on that carb. the upper one is the mixture. i find giving it 3/4 turn out is where they run the best with most rpm. then u slow down or set the idle to 400 rpm with the small upper screw. carb is always last to adjust after all the other settings, like points then timing. changing point setting which is the dwell the amount of time the points are closed also changes the timing , not a lot but a few degree's. your valve setting is .017 hot. info for you as u say u have electronic ignition.

 

[560Dennis]

some low cost and effective solutions
Look at spark plugs (best method I can recommend) of the tractor AM and compare to Tractor BM . Set of new plugs would help to see what you need to do . Hot rodders use this method and have written very good articles ( I say hot rod cause I think it easier to find spark plug solutions written online.
Also if (or get infrared thermometer’s) and compare exhaust manifold temperatures @AT local auto parts ,they are not much money $20 compare A And B . A lot of other uses for the thermometer such preheating for welding.
keep us informed on your progress ,helps others