Quote:
Originally Posted by big job
My 2 cents, go back to reply #21 pull throttle down key off put hand over carburetor you have to have some suction there. If not forget the carburetor. The intake has to suck and the suck which sucks fuel from the main jet along with air we breath then the plug sparks and it goes boom so simple. I do the simple, like squirt couple pumps of oil in all cylinders
plugs back in then do the suck test > better or the same. If the same, has to be valves
are not sealing or fully seating probably from sitting so long. Very easy to pop the head and pop the manifold off gaskets are cheap. My next red neck test is to put shop air
in each cylinder listen for air from carb and air from the exhaust pipe thats valves and
probably some air from the oil fill cap tells a lot if you don't have a compression gauge.
Wops I should have said to use shop air before pulling the head.
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You can also try the below before pulling a head. Yours has pretty much sat for at least 20 years. The head may be extremely difficult to pull.
Alternate ways to check valve operation, and without removing the head. Remove the spark plugs, gas off, ignition off, and stick a borescope (they are inexpensive) through the spark plug hole and crank the motor. Observe the valves in each cylinder to see if they are completely opening/closing.
Another check - after draining the motor oil, gas off, ignition off, remove the valve access cover, and crank the motor and observe the valves.