1990 Merc 200 xre efi
Motor starts & runs just fine, but once clearing the buoy line it will not take the throttle. Can only get 1800-2000r's. Bogs as if dragging the dock along with me. Problem started 5 years ago and was intermittent for years. I would stop & fish for 1/2 hour, start back up and it would run like a scalded dog the rest of the day. Problem gradually got more pronounced until now it is constant. I have replaced coils, switchboxes, plugs, all fuel lines and all filters. I am a mechanic, but this one's beating me up. Help???