Your best bet is to take the bolt to hardware store and match the threads with a tap.

I just did the same thing and fixed it two days ago! I bought a new bolt from Briggs dealer (less than $3). And I bought a tap from local hardware store ($9). Sure beats buying a new crank ($167)! For more info, check out this link to see my post on this issue.

http://forums2.gardenweb.com/forums/load/lmower/msg0623170221386.html

i got other questions.what puller do i need for this motor?for the flywheel the 1 with 2 hole on each side and hole in the middle wont work i dont think.becaues i have the flywheel that take the large bolt and plus at the top of the flywheel has like 1 or so i would call a like cup.

A Briggs dealer can get you a flywheel puller. Just tell them which engine you have. They are $10 or less. It is basically a plate that pushes down on the flywheel bolt while two screws are screwed into the smaller holes in flywheel. I've heard that a steering wheel puller or harmonic balancer puller will work too. You can buy or borrow from auto parts store. Whichever method you use, just make sure the flywheel bolt is tuned into the threads pretty far so you don't damage threads on bolt or crank.

ceesneezy what size tape did you ues the guy at the store know nothing and give me a tap looks to big lol they need hire someone with exp at this job.

9/16" 18 TPI (Threads Per Inch) tap

hey thx i got the crank threads fix.took me while find tap was dealing with dumb ppl whole day guy in store couldnt even figure out what size it was.sometime i think they just hire these guy off the sidewalk for gosh sake lol the first time give me a 5/8 i took back no way this the right size finally got 9/16 18 after all the hassle.working on pulling the flywheel bit hard task.

Glad to hear that you got the threads fixed. Yes some people aren't very knowledgable especially at the big stores. That's why I called two different smaller local hardware stores to get my tap. Good luck getting the flywheel off. If I had to do again, I would have bought the $10 flywheel puller from Briggs or made my own puller.