Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I have a 12.5 hp I/C  Briggs on a riding mower. When I started the mower it fired right up but was running roughly like it had no power. I throttled up and down a couple of times to see if it would even out and it didn't, so I took the air cleaner off and throttled up and down again and I got a puff of white smoke out of the carb. I could not get it to turnover at all after this. I figured she just blew so I walked away. Knowing that I am very consistent with keeping the oil changed in this rider I started back at it today. If I take the spark plug out it cranks over fine and has compression out of the spark plug hole. When I lifted the tractor to check the underside I found a piece of fence wire on one of the blades. Did I shear the flywheel key or where should I start?  thanks.

is the blade direct drive from the crank?,   If not...  you did not shear the flywheel key.    How long has it been since you ran the mower and it ran right?  Is it overhead Valve?

It could be a gummy valve,  a loose valve seat or just a spoonfull of water in the carb... 

Friiy

It ran perfect previous to this incident. It is an OHV engine and it has a 36 inch deck, dual blades belt driven from the crank pulley. When it blew the white smoke out the carb it had a spray of oil in it also. Thanks for your reply.

How old is it?....What model of Briggs is it?  Does it still have compression?

Friiy