hello I just bought a 1985 boat and motor. I replaced the four plugs, fuel pump and primer bulb just as a precaution. unloaded her and and started the motor. immediately the motor started running rough. it sounded like the thing was sneezing. it would run and then sneeze. i noticed it even blew off one of the vaccum lines. anyway i put her in gear and it would pick up speed a little but when i went to increase the speed it would bog down. i kept on moving the throttle back and forth then all of a sudden it took off like something was chasing it. awesome power. then when i back her down to neutral and try to go again it would do the same thing. I again played with the throttle back and forth slow to fast. it would bog down and then shoot off like a rocket again like nothing was wrong with it. I would appreciate any help with this.