Troubleshooting an acceleration bog/hesitation

Pump diaphragm is new, and I’ve had the issue with two different diaphragms in there. Could try replacing again though. Adjusted linkage for zero tolerance (with throttle at idle position), and verify first movement of throttle initiates the pump squirt. And I think the fact that I DO get an initial surge of acceleration immediately I think suggests that I am indeed getting a strong squirt off the start.

Yup, I’ve actually rebuilt it twice now! Couple more things to try. Still need to check if the secondaries are opening too soon and watch the pump shot under a hard pull with the flame arrestor off (need a good day with two adults and no children in the boat which is hard to come by at the moment). I hate throwing parts at a problem but getting to the point where it’d be nice to try a new carb with factory specs, at least to confirm I’m barking up the right tree and have a better idea of the baseline I’m starting with. Like I said the boat was not running great when I bought it and it’s tons better now but not much idea of what others have done to it before me. There were quite a bit of tool marks inside the carb from previous “rebuild” efforts from previous “mechanics”.