Maxum 2400 5.0L Alpha engine loss of power
Engine under load will run at 2600 rpms then when I increase throttle rpms will drop a few hundred rpms. With no load the engine seems good with high rpms (very brief) out of gear. Boat is 2000yr with 270 hrs. Ran great last Oct. when I bought it. Carb. was just rebuilt, new plugs, wires, dist. cap and rotor.
Gas is good, new gas filter, gas lines from tank good. I found one bad spark plug crusted over and rechecked the plug after running engine as we were on the water adjusting carb. for a few hours. The prop looks good and the bottom has new paint. Outdrive was rebuilt in 2016. During all our testing on the water under load the rpms went up to 3600 then later after stopping engine we could only get 2600rpms. I have not run tests on fuel pump. Has anyone experienced this or have suggestions as to what to do next. I hope all the carb measurements are correct as we took the specks from on line video rebuild by a mechanic in-law of mine. Engine sounds good at idle and under load it still sounds good except for rpm problem. Thanks