Does not start
I have had problems not starting on the HT 80 CC type engines.
For me the problem is always the clutch adjustment. When you try to pedal and pop the clutch , the clutch slips and the motor will not fully turn over.
It will sound like it does turn over , but it does not.
Remove the cover and there is a set screw, remove it and turn in the star wheel a couple of notches and put the set screw back in.
Then try again