40hp fuel problem

[<cracklin>]

Just got new carb, spark plug, and boat was running great.

I have two -6 gallon portable tanks. When I switched from one to the other on the first trip back since repair, the motor won't maintain steady rpm. Seems to run better half throttle or less.
At full throttle, the minute the boat planes out it cuts out.
Idles fine and starts easy.
Could this be just the line and/or connectors?

[<Cracklin>]

anyone?

[<boats.net>]

check out the gas in tank does it have water in it and ckeck carbs and filter for water