Here's the problem:

Boat sat under canopy since labor day. Fire it up before heading out and it is a little slow to start but fires up and idles a little spuratic but nothing out of the ordinary so we head out. We make a few passes in the water and all seems fine until we sit for a few minutes while switching riders. When we turn the boat back on it is running rough and has no power at all. When turning the key to engage the fuel pump you hear it turn on but it sounds like it is surging from not getting enough fuel, we put in 15 gallons before heading out. There is a major vibration while the motor is running and the exhaust note has completely changed. It sounds like the exhaust is packed up but that doesn't explain the motor running fine for the first 30 min. or so.

340hp FI
175hrs

Thanks for the help