I have a 1989 force 125 on my boat 19ft, this motor has 2 carbs.I have a 3 cylinder force motor for parts and i dont know the size of the motor,but it has 3 carbs. will they innerchange with the 125motor? My proplem is that the 125hrse has a rough idle and sometimes will knock off and has a light missfire at idle.Engine cranks right up and runs great on the water from half throttle to w/o throttle with the exception of alittle miss then &again.