Do you have power to the coil when the key is turned off??? sounds silly but there could be spark still after shut down??Is the coil "hot"/powered all the time,this I dont know!!
How hot is it running??? who knows but something has to be igniting the fule after the key is shut off and power removed.maybe!!
Im working on a crapsman for a friend that does this,great big jump out of the seat POP!!
Do it all again ,carb adjustment,timing.
Maybe the points sliped bit.
I know not much help,and Im no expert!!! the expert guys will come along,LOL
Rember when we were kids and we would shut off the key in the old stick shift carburated trucks,pump the gas,leaving it in gear,an then turn the key on to get a big old back fire!!!
the raw fule was pulled through the engine into the exaust where it would ignite!! I blew apart a muffler that way!
Good luck CBH
Jason
__________________
Jason Davis
:biggrin2.gif: Just one more !! 
|