also check the power valve in the carb. make sure it squirts when you throttle up. you can check this with engine off and look into carb and watch for it to squirt when you manually work throttle linkage. also check to see if intake manifold to head gasket is leaking. way to check this is to idle engine and take a can of spray ether and spray gasket area between head & intake where gasket is. if engine revs up gasket is leaking hence the problem. these engine are notorious for leaks in the intake-exh. manifold areas.
