1994 Evinrude 150 Intruder E150GLERV running lean..maybe

[Mleve]

First time caller, long time listener looking for thoughts. I'll try to be complete. 1994 E150GLERV 150hp Intruder with a rebuilt powerhead approx 100 hrs ago has run great for the 4 years I have owned it. This spring when I fired it up fuel was leaking from the carbs. I rebuilt all 6 carbs using Sierra rebuild kits. Fuel leaked worse. Replaced all fuel bowls. No more fuel leak. Timing and carb synching was checked and is correct. Float height was checked and set to float being even gap with carb body when inverted. Issue is it seems to be running lean but I am not certain. Since the carb rebuilds and new bowls the idle speed is slightly lower in gear @ 550, 700 @ idle but smooth. Engine will run a while in gear at idle but will eventually die. No coughs, sneezes, etc. Starts again immediately without enrichment. I have adjusted idle mixtures in the water, in gear, at idle and am approx 4 turns out on each carb which is where they were before rebuilding. Compression is even across all cylinders. Plugs are Champion QL78YC and have also run with a new set of QL77JC4. No difference in either plug. Under load the engine also feels like the engine has a cylinder that is coming on and off but power is not really low. Stills gets to 5400 WOT. I thought the cylinder on/off feel was only happening at 3000RPM but last time out it seemed more random...both how often and what RPM but never seems to happen below 3000. I thought maybe I was feeling the timing shifting into a more advance curve but never remember feeling it before this issue. Engine runs smooth at all RPM ranges. Last time out I tried to power load onto the trailer and when the throttle was opened the engine would die. Again, it would fire right back up but die under the load of power loading. During the carb rebuild I did not replace the throttle body to intake manifold seals and think I may have a slight leak? At this point I plan to take everything back apart. Reseal all carbs again using genuine Evinrude kits and replace the throttle body to intake seals. While everything is apart reclean each carb thoroughly with carb cleaner and compressed air. Again, I tried to be thorough in the description and my thoughts but wouldn't mind anyone's opinion if this sounds like something you've run across before.