Not a bike but next best thing

[pc220]

I have a ride on mower with a 10hp Briggs & Stratton engine, vertical shaft. It starts and runs no problem but when running the exhaust glows red hot.Im no expert but i pretty sure it shouldnt be doing that.Also it backfires and blows flames when I drop it down to idle. My first thought was that it was just running rich. But after stripping and cleaning the carb and fiddling with the mixture screw it has made no differance, lean or rich it still hot as . The engine block doesnt seem to be overly hot just the exhaust. Also to my ears the engine sounds to be racing.
Have had the head off and saw nothing of concern, no excesive carbon build up and valves look ok and go in and out as they should. No oil in the bore and piston is in good nick.
What am I missing ?

[Motu]

Has this just happened,or have you just got it? More like retarded timing,how old is the engine? It shouldn't have points in the last few decades,but check the gap if it has.Otherwise check the flywheel key.Also check for inlet leaks,it could be running lean...double check the head gasket seeing as you've had the head off.Check valve clearances,and valve seats...sometimes they come loose.

[maggot]

Turn it into a bucket

[SMOKEU]

Do a skid.

[slofox]

Has this just happened,or have you just got it? More like retarded timing,how old is the engine? It shouldn't have points in the last few decades,but check the gap if it has.Otherwise check the flywheel key.Also check for inlet leaks,it could be running lean...double check the head gasket seeing as you've had the head off.Check valve clearances,and valve seats...sometimes they come loose.

Wot 'e said.

[pc220]

Has this just happened,or have you just got it? More like retarded timing,how old is the engine? It shouldn't have points in the last few decades,but check the gap if it has.Otherwise check the flywheel key.Also check for inlet leaks,it could be running lean...double check the head gasket seeing as you've had the head off.Check valve clearances,and valve seats...sometimes they come loose.

Cheers for the advive Motu. Just checked the valve clearance and exhaust was bang on, but inlet has no clearance at all. So guess its off with the head again and sort that out.

[pc220]

Do a skid.

HAha, actually when I first got the mower I figured out how to do a wheel stand on it. But when I decided to show off my newly found talent to the mrs I had a navigational error and ploughed straight into the side of my work ute.Luckily that did buff out.