Help landlord quit and won't restart , snowsa pili

[johnb110 0]

I took my 10 h.p. (243431) landlord out for it's first job of throwing snow last night. All was going great for about 10 feet of blowing when a mighty backfire occured and she quit. I just overhauled the motor , replaced ignition parts,cleaned up head and valves as best I could without dissasembling. It would start and run without even hearing it turn over before this happened. There seems to be good spark, it will fire the very odd time but not start. It's getting lots of fuel, floods like crazy if I try too hard to get it started. I took the head off again and everything looks O.K. that I can see. She is a bit of an oil burner and I did dump a bit of instant pistons in just before I ran it. Could something have happened to the timing when it backfired. Anyway any suggestions on what to try next would be greatly appreciated. Thanx in advance., long time member John

[BenB 3]

John Just a wild guess..... could the backfire cause the flywheel key to shear, especially if the nut had not been tighten to the proper spec ? That would affect the timing. Ben

[MPH 12]

Bens wild guess sounds likely, You should be able to ckeck that by seeing if you spark occurs at top dead center or just a bit before, not positive of the timing on these ole briggs. What is instant piston???STP.MPH

[PatRarick 1]

John, I would first check to see that the point gap is properly set. Possibly, you didn't tighten them sufficiently? That will throw the engine out of time and create the backfire, intermitent spark, etc., that you describe. If all checks well there, then the flywheel key would be the next possibility. That is a heavy flywheel, and if it was not tightened to torque, it can slip. Pat

[JeffG 0]

I agree, probably the magnesium flywheel key.

[Les 4]

When I rebuilt a Briggs several years ago, I had a partially sheared flywheel key, I had spark but it was very weak, not enough for the engine to start. Briggs are a little finicky about point gap.

[johnb110 0]

Thanks guys some good suggestions,I totally gapped (no pun intended) to check the flywheel, as I've never sheared a key before. For MPH instant piston is just what we call the so-called engine restore or equivalent products up here in Ontario Canada.