Pull string yanks back

ColeMidTN

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Hi, new to the forum. Just picked up a used Cub Cadet 11A-MC056 959-468 in non running condition. It had a broken handle and hard to pull pull string. I believe the engine model number is 1p70FUA.

So far i have replaced the broken handle, replaced the fly wheel key (even though the original looked fine), adjusted the valves (intake at .006 and exhaust at .008). I think i did this correctly (Put my finger over the spark plug hole and rotated the engine until compression stroke, placed a plastic straw in the spark plug hole and continued to turn until the highest point to find TDC). The edge of the head makes this engine difficult to get a feeler gauge in.

I can get the mower started and it runs fine, but occasionally the string still yanks back very hard (feels like it's going to break some fingers!)

Any suggestions on what to do next? The blade does not have any chips or dents in it to indicate that the PO hit something. Should i remove the blade and inspect the adapter keyway? Or would this even make a difference? Any help is greatly appreciated! Thank you!
 

ColeMidTN

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Well I pulled the blade and the adapter keyway looks fine, still fits the crankshaft snug.
I finally found the correct engine model number as well. It is not a 1p70FUA but a 1p70M0. I am having trouble finding the valve clearance for this particular model. Anyone know if it is the same as the FUA?
 

ColeMidTN

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Mark, thank you for the suggestion. I found the MTD manuals for the P70 series engine, and valves need to be set at intake - .003-.005 and exhaust - .005 - .007. I went back and readjusted the valves, spun the flywheel around a few times and double checked.
Tried to start the mower and still same problem.
It will start and run, but the string will still violently jerk back from time to time. Only other thing I can think of is to tear the engine down and check the compression release lobe & spring. If anyone else has any suggestions, I would love to hear them before I take the engine off the deck.
 
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