Hello,
I have a troy built walk behind lawn mower, The engine is unmarked, but I thought it was a Honda, when i went to get parts for it they said the Numbers i gave them was for a brigs. I'm not sure how old it is but probably about 5 or 6 years. on the front of the valve cover it says OHV. The only numbers on the engine are on the top of the valve cover which are:

99772 0625 01
94061404

When you pull the engine it doesn't start, or even try to. If you spray starting fluid in it, it will backfire sometimes, but thats it. I've cleaned the carb with carb cleaner. and made sure it wasn't clogged anywhere, I don't think the carb is the problem.

I noticed that it seems to blow air out of the carb at the point in the cycle right after it sucks in air. so I took off the valve cover and loosened the nut on the bottom valve rocker. Now it doesn't seem to blow out the carb at that point, but It sounds a little like it could be blowing out at the exhaust. still didn't start.

Any help would be much appreciated.
Tom

Have you possibly hit something with the lawnmower?.Sounds like it's got a shared flywheel key. Throwing it way out of time.Take the spark plug out,tilt
the frame it up,spin the enine and look to see if the crankshaft is bent.BTW,you do have a Briggs engine.