Throttle body opening hissing sound on mpi will not idle correctly?

[stagecoach]

I put in a new raw water pump last night. went to test drive and the boat was shaking running rough and a loud air sucking sound under flame arrestor and body
opening. indmar 350 mpi assault on a 2000 comp. what is my next step. any input would be great thanks. enjoy the holiday weekend hopefully i can get on the lake.

[michael hunter]

Sounds like a vacuum leak . Take the flame arrestor off and look for any hoses or fittings open . I use carb spray to sprat around the throttle base to find leaks?