Suzuki Df115 problem on takeoff

[dh99]

I purchased a used boat with a 2004 Suzuki DF115 and I am having some problems on takeoff. When I take off the motor is sluggish and the rpms' stay at around 2500 and then all of a sudden the engine picks up and takes off.

I don't think its a problem about being underpowered or the wrong prop, cause it doesn't always happen. It seems like its not getting its gas and then all of a sudden it gets it. It only happens on take off.

I brought it in to the dealer, changed the water pump impeller, the low and high pressure fuel filters and the spark plugs and it is still doing it.

Anybody know what can be causing this? Bad Gas? A sensor of some sort.

Any ideas on what to check or do would be appreciated

The motor is on a Lund Fisherman 1800 if this helps.

thanks

DH99