94 25HP Yamaha "surging at WOT (75+ on throttle)" but runs great otherwise

Has been a great motor. Spring cleaning includes gear lube, water pump, prop service, new motor end fuel lines, new remote tank, new boat end fuel lines (w/ water separator), fuel filter, plugs, carb kit (for both), carb disassemble, soak, and compressed air cleaning, and new fuel pump kit. No issues last season. Spark test good, compression good.

Test drive results.........starts first pull, idles like a kitten, smooth all day long UNTIL 75% plus on throttle and it surges as though it has a fuel restriction. Priming hose ball has no impact when it acts up. It does not cut off. The only issue seems to be WOT (75% + on the throttle). My guess is to tear the carbs back down and redo.........what say those with way more problem solving skills than me? Thanks for any advice.

There is dirt before the seat and needle in the carb. Take the carbs apart and back flush the needle valve seat. Put a clean paper towel there to catch the debris.

I can take it back down and check/clean according your advice. Thank you. Is it possible I have the pilot screw incorrectly adjusted for both carbs and this could be the culprit? I have three yami's (90-25-9.9) and ONE manual. The pilot adjustment (# of turns) is not listed in the manual for the smaller motors. Thought I should ask and adjust to specs prior to my two hour labor investigation again. Appreciate your help.

I have experienced this problem with a couple of carbureted Yamaha Outboards. I Always find a piece of dirt between the fuel line and the seat. The adjustment you are talking about is not for WOT.

Thanks again. I have completed the carb cleaning again. I will not be able to test run it until next weekend as the weather/time will not allow. I am setting the pilot screws at 1and1/2 out until I can get clarification. Thanks for the support.