My '94 225hp TXRS dies out at 4000rpm on my 24 Grady. In sum:

Last week it ran fine on a separate tank, but when reconnected to the main, it died and wouldn't restart. So, we cleaned and rebuilt the carbs (pretty gunky), drained and filtered the fuel, and rebuilt the three fuel pumps on the port side of the engine (they looked like they needed it when opened up). Fuel in the port transom mounted filter looks fine, no clouds, no water, no particles.

Now, it starts and runs ok in the driveway, but runs rough at idle and low rpm. On the water, it smoothes out at about 1200 to 1500 and above until around 4000rpm. Then it dies out as if it's not getting enough fuel. The ball is NOT staying firm. After that it will start back up no problem, though the idle is rough still. If one person pumps the ball, the engine will run up to 4000 and above, but we didn't want to push things. No alarms.

Any help would be appreciated, I think the next step it to check the fuel lines and sender from the onboard tank. Any other ideas, input? Thanks!