Topic: Won't run after breakin

[Smowkin Joe]

12 hp flat Briggs, won't start and run again after initial breakin run. Checked spark, changed plugs 3 times, two brand new coils, changed the flywheel, tore the carb down 3 times, fuel is fresh, checked for broken valve springs, compression is fine, it didn't smear the flywheel key like I expected to find either. It ran fine 2 weeks ago when we shut it down. Went back 2 weeks later to lock up transaxle and expected to get it on the track for some fine tuning and can't get it to run to save my life. I'd pull my hair out, if it was long enough to get a hand full of. It's pretty much a stock engine with minor port and head work and walbro carb. We did get it to hit about 4 times after dribbling some fuel directly into the carb, but that was it. Any ideas? I'd hit it with a widdle hammer   if I thought it would help.

[George Herrin]

Valve not seating sounds to me like or intake leak possibly

[Smowkin Joe]

That's the only thing I could come up with...I just didn't want to have to tear it down again. I'm kind of suspicious as to if someone else in those two weeks decided to run it, and not tell me about it. Of course NOBODY will fess up to that if that's the case. 

[Huffy044]

Take a spark plug, knock out the guts, weld in a air fitting, induce air into the cylinder, listen to where the air comes out, fix the leak.

[Smowkin Joe]

Ok. It was D: none of the above. It is surely a lesson in, checking the SIMPLE stuff FIRST. After if was determined that the original coil had gone bad, a new, aftermarket coil was put on. What I didn't see before, going through all the other checks, was that the replacement coil(s) was installed UPSIDE DOWN.