Power loss at hole shot

[gottagasit]

Thanks in advance for your help. I have a 1990 Evinrude 200XP on a Hydra Sport and I'm losing power at hole shot. When I hit the throttle from stop it has a hesitation and seems to dog out until I hit plane. Once on plane , I can pull the motor to 5100 rpm's with trim and top out at about 50 mph. The engine is on a manual jack plate almost all the way down. I tried raising the engine higher on the jack but get cavitation at hole shot. The hole shot is my issue...with my son on a tube the boat has a difficult time getting on plane. I bought the rig in March and had no issues then. Took it to a certified dealer and he replaced the gasket between the powerhead and mid unit(it was leaking a significant amount of water) and I was sure the culprit was from pulling water into the carbs. Got it back today and tonight I tested it ;it is doing a little better, but still slow at hole shot. I'm open for ideas before I take it back to the shop with an open check book. Thanks, Doug.