i have a 1989 force 85hp,used to run good then all of a sudden boggs down an stalls in forward gear.i just replaced the water impeller.fuel pump flows good,put new plugs in,new primer bulb,good spark,idles ok,throttle cam pick-up point matches,throttle valves in sync.all this dose't matter because run great in reverse! WHY IS THAT dosen't the timing stay the same no matter what gear selected? linkage seams fine both ways HELP ME!