rough idle

[gabe4560]

Hi, last weekend i was on the boat and when i started it, the idle was almost perfect the only issue is that i have to pump the handle 2 or 3 times to start from cold and accelerate immediately to get fuel to the carb and get it to idle, then after drive to the sandbar 40min from the marina when reduce the throttle to idle the engine dies.
Please some ideas, already rebuild the carb, and had to install the old plunger because the new one broke the rubber after 2 runs.

 

[Oshkosh1]

Re: rough idle

Check the needle/seat for contamination/improper sealing and float drop/height. Assure idle mixture screw(s) are set to establish highest vacuum or smooth idle by ear. When rebuilt did you ensure ALL jets/passages were cleaned AND cleared with compressed air?

Check to make sure the choke is set correctly.