G14a won't start

[Old but persistent]

Have a 96 G14A that pops back through the carburetor when cranking and won't start. I pulled the head, lapped the valves and set to .004 - no difference, still pops back. Do I possibly need a new TCI unit? How do I confirm, they're $$?

Secondary issue, head bolt near carburetor won't hold 20psi torque. Compression checks at 125psi. Any ideas on how to repair bolt hole in head without pulling engine?

Thanks for your help.

Old but persistent

[Tinken]

What's your jetting look like? Does it start with quick start?

[Old but persistent]

Has good fire when plug is pulled and held on metal. Will not start with starting fluid. Pops a little differently with starting fluid, but still through the carb.

It was just running great, except a little low on power due to the 125 psi compression. The push rod for the intake valve had come out of the seat and it quit so I put the rod back in the seat, reset the valves to .004 and it started right up and ran fine. My daughter and her husband took it for a ride around their farm and it bogged down and quit as they were going up a hill. Since then, won't start and is popping back through the carburetor. Almost seems as though the timing got messed up and it's firing when the intake valve is open?

Have worked on mower and old car engines for many years but this has got me stumped. What controls the timing of the firing?

Thanks.

[Old but persistent]

Noodling through the service manual and came across a spec for the engine bracket adjustment. It calls for a freeplay of .008. Checked mine and it's looser than that. Could this in any way have anything to do with the starting? Don't understand how it could but appears there is more about this Yami engine I don't understand than do.

Thanks.