A compression reading of 65 psi is low BUT perhaps the gauge is faulty.... also compression depends on the speed of which the engine cranks over, also the cylinder walls may be extremely dry.
Note that your engine has a adjustable slow speed needle valve (top of carb)... Instructions are below.
Note again... laying in a horizontal position in the bottom center of the float chamber (way in back of that 7/16" clotted hex screw) lays the high speed jet. I suggest that you make sure that it is clean by carefully using a piece of single strand steel wire to clean it as solvent just doesn't do that job properly.
(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)
Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.
Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.
Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.
When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
