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JD 420 RPMs wide open

1039 Views 8 Replies 6 Participants Last post by  DTapley0417
Hi all

I picked up a 420 with a P220 in it a few months back to snowblow with. I mowed with it one time and during the mow the RPMs went through the roof. I had to turn the unit off in fear it would blow up. Since then It would idle and it would begin to hunt or surge. Once any throttle is added it runs 100% wide open and will not come down. I checked the linkage but everything seems to be in the correct spot.

Things I did to resolve:
Cleaned carb
New gaskets
Reseal intake
New gas lines

I came to the conclusion it was the flyball spacer. I removed the engine and got to the spacer but it’s in tact and the spacer will barely even budge. Could the spacer still be the issue? What else should I look for to cure this issue? Any help would be greatly appreciated
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if the governor plate on the crank barely moves, thats most likely your issue... it needs to be able to move freely to push on the governor arm to regulate speed. if its stuck, it wont move out with the balls and close the throttle at the desired rpm.
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