Try using a screw type hose clamp (IDEAL or similar). Tighten on the piston/ring assembly, gradually loosen until you can slide the piston home, and then unscrew the clamp completely to remove.

ok i will try the hose clamp idea. i broke a ring off trying to get it in. i got another question. can i eliminate the governor?

Do not eliminate the gov unless you wanna eliminate the engine altogether.

Instead of manually removing carbon like that you need to start using seafoam in the gas/oil mix at 2oz per gallon for maintenance....no more taking engines apart.

i had someone give me the mower and it was loaded with carbon.