I have what is basically a 1957/59/59 OMC 35 with a high speed problem. After building the motor out of spare parts, it ran fine for a year them mysteriously will only run at what seems to be about throttle saving speed.
I checked all the linkages and it is fully opening the throttle.
I replaced the plugs and now boots with new ones.
I took apart the carb but found no problems. I ended up swapping the carb for a known good carb that I opened up to be sure and repacked the needles, however still the same thing.
It feels like the high speed is just out of adjustment and if I could just find the right spot..., it is planing the boat but not developing full rpm and is running rough at all speeds.
I am pretty sure I have ruled out the carb as the problem.
Next I will pull the mag plate...
I have not run into this before and am stumped... it is putting out too much power to be dropping a cylinder...