Having troubles with motor running out of fuel at high RPM's or under heavy load. When it begins to act up, pumping the primer bulb brings it out of it. Have replaced fuel pump diapragm and check valves. Cranking compression is 130 across the board. Fuel tank vents operate. Line and primer bulb to fuel pump are new, as well as line from pump to upper carb. These lines had crimped ends from the factory, they were replaced with barbed fittings and clamps. (Possible problem?) Primer bulb will never get hard, but will not flood engine if you keep pumping it. Engine starts right up and idles great. Engine sat for about 5 years.