i recently traded for a 1965 evinrude fisherman 6hp. the motor starts and runs great at slow idle or wide open. when i put the engine in gear it pushes my boat fine but at a slow speed. maybe 5-7 mph. the engine sounds like it is running at half throttle when in gear and pushing the boat. Any ideas what could be wrong? i know little to nothing about boats or motors. this is the 1st 1 i've owned. also, i am looking for a prop. for this motor. where could i find one? nothing wrong with the one on the motor but i was told that it should be a 3 blade prop instead of a 2 blade used on this motor. i honestly dont know....