1986 115 evinrude power loss at full throttle

Ive had this boat for a couple

Ive had this boat for a couple of years and this if the first time ive had this problem and it has happened the last two times i went out. Whenever i get up to the top rpm range it will suddenly drop down in rpm quickly and then rev back up again. It goes from like 5000 rpm to 3000rpm and then back up again. It acks like its not getting enough fuel but i replaced the plugs and fuel filter and it still does it. It does it when the tank is full and it gets worse and less fuel is in it. Also it only does it when the engine in the water ive ran it out of the water at high rpm and it dosnt want to act up has anybody else had this problem.

You had best not run the motor

You had best not run the motor at full throttle out of the water. Start your trouble shooting with a compression test.

but would bad compression make

but would bad compression make it run bad all the time

Well if there are pieces break

Well if there are pieces breaking of the piston rings and getting into a spark plug you loose spark for a moment. Good trouble shooting starts with a compression test. But it is your motor and your money so I guess you can start replacing parts and hope you stumble accross the problem. A compression test cost essentially nothing.