My 98 honda bf 40 falters under load

[Tom turkey]

My 98 honda bf 40 falters under load. It revs in neutral over 5000 rpms perfectly but in gear it wont go over about 4200 in gear. I was running all day fine and then on my way back in it fell on its face and i limped in. Then i replaced the plugs and now it goes to 4200 but just doesn't have the power it should... Any thoughts?

 

[Tom turkey]

I had the carbs torn apart and cleaned and re needled late last summer and it ran fine. Replace fuel filter. Drained the bowls for winter and fogged the cylinders. A week ago i put in a new pump kit and thermostat and this was my first trip to the water. It ran normal for a half tank of gas, 6 gallon can and i had just got the gas also. I was running back on rough water at about 3/4 throttle for five or ten minutes when it just seemed like it started bogging and sorta missing. Thats when i replaced the plugs incase they were fouled from the fogging oil. It seems to run a little better but still want rev over about 4200 under load but in neutral it does 5500 smoothly