Not sure if I found my problem but the exhaust valve has almost no clearance, also I noticed that the valve spring and retainer clips are different sizes for the intake and exhaust, I checked these on the parts diagram and they seem to be correct. Guessing it has something to do with being an I/C model as I have never come across this before when working on cool bore engines. I will assess the valves and get back with a conclusion.
Update: I cleaned the valves gave them a quick lap and grinded the exhaust valve to the correct clearance, I also gave the carby a quick squirt and blew it out with compressed air. Not sure why but it had 2 diaphragms so I pulled one out, end result it started first pull which it dident do before as I had to pour gas down the filter to get it to start but it won't idle or rev at full throttle it just sits at a steady slow run and blows black smoke. Also I did another compression test and still got 50psi my other 5hp cool bore reads 80psi so I'm guessing rings are shot on the I/C engine.
