I received a generator that was about 5 years old and 4 hrs of runtime on it from my father. He only started it up once a year. Last attempt it didnt work, the intake valve was stuck. He freed it, adjusted everything and got it running briefly before it died. It is now my project. The exhaust valve stuck, pulled the head and cleaned up all the varnish and gum and now both valves move freely. I adjusted the valves per briggs manual, 1/4" past TDC .004 intake and .009 exhaust. The compression gets really hard,and eventually the rocker will open a valve and stop. Neither push rods move until I loosen the offending rocker enough, then theyll resume movement until the other valve does the same thing. It almost seems like the pushrods are getting stuck or falling off the tappets until I loosen the nut and they drop back in. As I loosen the nut, the valve slowly returns to closed position as I loosen. when the pushrods get "stuck" Im still able to push on the valves and have them fully open and return back to the rocker, so valves arent getting stuck. Piston had no scoring or marks, so valves didnt hit it. Valves appear straight.

Valve guides are tight. Not sure how its supposed to look, but intake is flush to the head, and exhaust is raised maybe 1/8"? I didnt measure, but retaining cap doesn't hit it

engine model is 121012 I think. one of the 120000 series horizontal shaft engines.

Things i've tried: Pulled head, carb cleaned valves and guides. Valves move freely. Pushrods not bent. Tappets move as they should while rotating. Adjusted valves to spec several time. Adjusted exhaust to .006 just incase .009 wasnt engaging the ACR, same problem. Tried at 1/4" past TDC, 1/4" before TDC, and TDC. still the same problem.

Im completely stumped on this. With 4 hours of intermittent run time over the years, I dont think there'd be anything wrong with the cam. Any suggestions?

Thanks