jumped timing

[Slick1951]

have a melroe 500 with a kohler k662 and a wico xh2485c. it keeps jumping time. mag is sparking good,has 120 psi compression, getting fuel. ive always been able to bring ole frankenstein alive but cant figure this out. any help greatly appreciated, thanks.

 

[foton]

could the bushing in the mag. be worn enough to do this? the engine mag I had it was causing the rotor to eat the cap, timing was all over ,had to replace mag been good since.

 

[Slick1951]

could the bushing in the mag. be worn enough to do this? the engine mag I had it was causing the rotor to eat the cap, timing was all over ,had to replace mag been good since.

Thanks for your reply. i have not taken mag 100% apart yet, but no damage that i can tell. Spring is good,put another half turn on it. Lag timing is at 20 degrees according to specs. Spark jumps 1/4 inch bright blue. Today i turned flywheel by hand, belt pulley turns exactly the same time with no play. but i did notice that there was a couple of inches of play from side to side when turning the flywheel before it actually engages cam gear. Maybe some teeth have broken off on the crank or cam gear. Got 125 psi compression on both cylinders and getting fuel, just do not know why it will not even fire at all.

 

[foton]

Thanks for your reply. i have not taken mag 100% apart yet, but no damage that i can tell. Spring is good,put another half turn on it. Lag timing is at 20 degrees according to specs. Spark jumps 1/4 inch bright blue. Today i turned flywheel by hand, belt pulley turns exactly the same time with no play. but i did notice that there was a couple of inches of play from side to side when turning the flywheel before it actually engages cam gear. Maybe some teeth have broken off on the crank or cam gear. Got 125 psi compression on both cylinders and getting fuel, just do not know why it will not even fire at all.

I do not remember but I assume there is a flywheel key maybe that is sheared or bent, on tear down make sure to check that first.