i have a 1988 45 hp mariner engine that i can not get to run right i have had it at several shops also with no luck the motor has 120lbs compression on all 4 cylinders but does not build up the rpms like it should you can play with the throttle and get it to go to about 4500rpms but never really opens up the motor is really flat and floods easally have had carbs rebuilt and every thing checked out and they say nothing is wrong dont know where to go next