Pulled apart the carbs, expecting them to be completely filthy and plugged, but surprisingly, they weren't bad at all. Some staining on parts of the float and bowl, but not nearly as bad as I would have expected.
2 of 3 main jets had a little fouling, but not bad. The jet tube were open on 2 of 3, with very reduced flow in the 3rd. But still, not really bad enough to cause the fuel starvation issues when revving up in gear i would think.
Regardless, I got all the carbs cleaned, old gaskets cleaned off, and just waiting on new jet tube and gaskets to arrive in the mail to reassemble.
My buddy is wondering if there might be a vacuum leak, so he is pulling the schematics for the carbs from that manufacturer to see if he can locate a problem.
But I fear that rebuilding the carbs is not going to solve lack of power when going up to speed. Will check compression on the cylinders next week, but I just don't see how that could be an issue as the motor starts right up, idles perfectly and quietly, and is responsive when revving up in neutral. Just can't get enough rps when under load to get the boat on plane.
(Any suggestions, I'd love to hear them!!!)