83 Mercury 50 hp low rpm at wot

[INDYCAVER1]

You guys go any suggestions on what to look for on my issue. I did compression check today and all 4 cylinders were 115-120. I finally got the tachometer working and me and my daughter went out today and at wide open throttle we were only running 2900 rpms. I took the carbs off and cleaned them and put new fuel pumps on both. I havent put them back on to test them but should have them back on to test it later this week. If I know the compression and fuel are good,. What can I check next. The motor is on 15 ft tri hull hul the prop is 11" x 13 pitch. Could it be the prop?

 

[INDYCAVER1]

I forgot to mention that I checked the butterfly's on the carbs the the throttle all the way up and they were almost all the way open. I will adjust it to make them go wide open when I reinstall the carbs. The top one was about 95 percent open and the bottom was about 90 percent open