I have a problem starting my big merc when its been sitting a while. I recently had the fuel pump rebuilt (diaphragm had a hole in it), changed out the fuel line and the bulb, and had the intake manifold gasket replaced (was shot and leaking).<br /><br />The motor has always been 'cold blooded', but has recently gotten worse and much harder to start. I suspect that the fuel bulb has air in it from when we replaced it. When pumping the bulb - it never gets rock hard anymore.<br /><br />When starting the engine, the engine will 'pop', and then stall, whether choked or not. The onloy way I have found to start it is to give the ball like 7-8 squeezes - but the ball never gets hard! Once the motor starts - it will run forever and never quit. I ran compression numbers on the engine not too long ago, and all of the cylinders were 110psi or more. The engine has fresh plugs and clean fuel.