Kohler 15Hp on Toro WB Bolt Specs HELP!!!

[MOW ED]

I have a 15HP Kohler from 98 and it is on a Toro hydro WB. The bolt that holds the electric clutch has went away and I do not know what replaces it. I ordered one from Toro and they sent me a metric bolt which is supposed to work in there but no-way. Too small. Its a 8.8metric 1.5 thread #10. Part number matches the book but it ain't right.

Can some one help me. The bolt is aprox 2 1/4". I am thinking mayby a 7/16. It starts to thread but is tight.
Is it a 7/16 coarse, fine or something else. This is kickin my butt.

Any help is greatly appreciated.

[smburgess]

Last week I replaced a 15hp Kohler on one of my walkbehinds and it had a label on it saying the shaft would one of two sizes, one was metric and one was 7/16 - 20 or 24. Sorry I can't remember the exact threads per inch. I hope this helps.