I feel I am having a run of poor luck this whether, one issue just leads to another. New issues today, once the engine was fully warmed up, I had been cruising at between 3000 and 4000rpm for about 80 minutes, I slowed and went to neutral for about 5minutes. The boat was idling at 800rpm, sounding very health. I then advance the throttle to take off and as soon as I reached about 2000rpm the engine would die back. I throttled back quickly and the engine although in gear recovered at about 1000rpm, Pushed the throttle forward again and the same thing. On the third occasion as I pushed the throttle forward I pushed the key in very quickly and not an issues the boat was straight on the plane and running smoothly at 3500rpm. I ran the boat for another hour at 3500rpm and drew along side a pontoon. Was tied up and in neutral for about 3mins, pulled away from the pontoon and pushed the throttle lever forward, again at 2000rpm engine died back to 1000rpm. Again I throttled up but pushed the key in quickly to give a quick shot of gas from the solenoid, no issues, boat picked up properly. Any ideas? Additional information: Engine runs great and pulls all the way to 6100rpm, I opened it to full throttle so see if the fuel pump was not delivering, but not an issue, was at 6100rpm for about 2mins. Plugs are tan, no timing issues. I think it must be fuel, but I have just rebuilt the carbs and it has run for 10hours since carb build without issue except for the occasions today.