Ok -- I posted a while back about this motor in the other section and noticed its the wrong section anyways
but here goes
Got a small 49cc Motor -- ran fine one night - turned it off all was well -- next time motor wouldnt stay running without the choke on (on as in Choke CLOSED Restricting airflow)
ive tried everything so far
Cleaned all fuel lines, petcock, filters
cleaned carb top to bottom and jets are perfect so is needle
Flushed Gas Tank out cleaned it up good
nothing worked so far
now I did the good old finger pressure test!
and oddly enough I can push my finger into the hole and keep it there - even with someone turning the motor over
I felt a little suction and a little pressure but that was it
so what ive done so far here --took off the Cylinder head, and Cylinder and took the piston head off (Left Rod attached to shaft - I didnt tear apart the crankcase)
what I found was this
Cylinder chamber walls perfect shape - no scratching, scoring, not even dirty!!
Cylinder Head (Combustion chamber) -- u can tell this motor has been used LOL - wasnt like caked on but there is a film of burned out oil and fuel
Cylinder Chamber and Cylinder Head looked normal
now The Piston was another story -- its got a thicker film of burned gases and oils on it and looks a bit nicked and dinged around the edges of the head -- the rings are good and it seemed to seal - but its a bit dinged in a few spots
however it looked right for having a good seal!!!
so im lost!!! -- are pistons supposed to be burned and blackened i mean what can be causing the loss of compression?
ive checked over everything i can think of on this thing to figure out Y it doesnt run without the choke on!
I did find one paper gasket that looks like its been there so long its pressed into the metal - but its the Gasket that seals Crankcase -->Cylinder -- so its Behind the Piston
is it possible that Pressure goes behind the piston too and if its escaping via that old gasket i can loose compression?
let me know
Thanks
SangrelX
Wanted to add this a Link to this image -- this is what the top of the piston looked like
http://www.bikemanperformance.com/im...iston_lean.jpg
not that actual piston but thats what it looked like -- just a film of carbon
and the spark plug is all full of carbon too but it does spark - but not a flat blue -- is it possible the spark plug cant keep up without the choke on?
im slowly learning more about small engine repairs