Craftsman tractor with Briggs 12.5hp blows oiland fuel out of the crank case breather

upupandaway

Well-Known Member
Joined
Jul 3, 2015
Threads
36
Messages
615
  • / Craftsman tractor with Briggs 12.5hp blows oiland fuel out of the crank case breather
stangnutlx1 - Yours sounds like the 12.5s I have. Take off the plate to the valve springs and check the gap of the intake valve. If no gap, file down the valve to produce the correct gap.

I got 4 of these back in the late 90/00's. All i got used that the owner tossed so they were sitting around for a while. Weird, but all the valve would stretch after my first cutting. Then on the second cut, producing these symptoms- spitting gas back to the air filter after running for about 30 seconds to start warming up. I filed down the proper gap and they run fine since. This would also explain the low compression - valve not closing.

Boudreaux In Eunice- this is where i came up with the crazy idea of using paper to confirm it was blowing back before taking them apart.
 
Top