1997 Force 50 HP

I have a 1997 50 HP Force on a 20' pontoon and recently had issues with declining RPM's 4000-4600 when previously it ran around 5200. Checked compression and have 110+ on both cylinders. Talked to mechanic and he said it would run on only one coil so you could test by removing each while running to see if either was bad. When removing top plug wire the motor continued to run but when I pulled the bottom plug wire only the motor died so I assumed the top coil was bad and replaced both coils. After installing new coils it does the same thing as before so I wanted to see if maybe I recieved bad information from the mechanic on how to test the coils or if I should be looking at something else in the ignition system that could be causing the problem. I'd appreciate any help or ideas.

Thanks
David

I would suspect a fuel deliver problem. I do not think a 2 cylinder engine will make 4000 rpm under load running on one cylinder.

Check fuel filters, pump, lines for blockage and ethanol damage.

Had same motor recently. Had a broken reed valve.

reed valves are the achilles heel of that motor. the way you know you have reed valve issues is you will have lots of smoke, a hard start, as well as fuel dripping out the bottom of your carbs. this may not be your solution but the force motors of that age are problematic. they are cheap mercs. if your super unlucky you have the cheap Chrysler, I know a thing or two about them on the carb/reed valve end of things so PM me if you need some help.