hi all, I bought an old 1961 s/c 15' jet with a 40 hp big twin. Engine runs well, but max speed is 19-20 mph. upon inspection, the throttle isn't being opened up all the way with the small linkage arms that also adjust the timing. The cable is adjusted properly, as the arm that moves everything is moving all the way to the stop and adjusts the timing all the way. so my question is , any reason why the throttle blade would NOT be adjusted to open up all the way? it is on a little shaft with an adjustable stop.