I have "MARRIED" a 1991 Kawasaki SC 650cc complete drive train to a 16'/50" Jon boat. Top speed of around 27 mph loaded with two people and gear. I have an issue with it seeming to run lean, I can hold the choke on the first notch and it runs ok. Sometimes after shutting down to fish, it was very hard to start. Rebuilt the carb and it is easier to start, but still seems to be starving for gas. I have ordered the block off for the block drain and inspected the reed valves. The reeds look like carbon fiber and seal completely, do not think they are the issue. ordered an intake gasket set. Going to put it back together and run it to see if the block helped. New to PWCs and would appreciate any thoughts or ideas, thanks.