I just completely torn down and rebuilt my FL250, but it wont start. Cleaned the carb, brand new intake manifold, fuel pump is working fine. I have 146lbs of compression (shaved head), and a nice strong spark. My problem is I have no suction through the carb to get gas into the engine. Any help is much appreciated. I can only suspect a leaking gasket between intake manifold and engine block or leaking lower end.