Are your enricheners working? I know you had some bad cables. Is it firing on both sides? Does it respond to throttle? or just die?
I fired up a 200 today also. I had it running the other day but only ran on the left cylinder and backfired once in a while on the right. I thought maybe a seal, didn't really know for sure. Pulled off the engine cover, clutch, crank gear, idler gear, and the valve housing. Seal looked ok. Took the valve off to make sure it was timed correct. It wasn't. It was off by one tooth. It was on the L mark instead of the R mark. Replaced everything and now its running on both sides.
Whenever you see messed up screw heads and know someone has been into the engine before, you never really know what to expect.