Swooshing noise.

[Three B's]

I'm a new 28 owner and have two questions. When starting off around 2000-5000 rpms I hear a noise which seems to come from under the back off the boat. It sounds almost like aerated water swooshing under the boat. The sound disappears when we get over a certain speed. Anybody else have a similar sound or is it a sign of a problem.(I've listened with the fishboxes open and it doesn't seem to come from the shafts or transmissions,not jackshaft model)
The other question is related to throttle control. Boat is powered by twin Cummins 250 4BTA's with hydraulic shift controls. Every once and awhile the throttle controls are soft and rpms don't pick up significantly until the boat gets out of the hole. Is this typical or do I have a fuel problem.

Thanks for any help. Totally liking the new boat, got my first Mako last week at the Fingers. Yahoo!

[Bullish]

I'm in Waretown too. Stay in touch. I usually go offshore without teaming up with anyone else but it would be nice to run tandem to the canyon. I have Volvo's but they also will not reach high rpms until she gets out of the hole. I could even say that there is a hesitation for 3 seconds just before she levels off. I have talked to mechanics that say there is a common Volvo problem that the compressors tend to cycle or click on and off just before planing so that creates the hesitation...but you don't have volvos so that's not your issue.

I'd like to know if the guys with 300 hp engines experience the same issue. My engines are 260hp.

I have not heard any swooshing noise that you describe.

[Three B's]

Noise description.

Thanks for the reply. The noise I was trying to describe is maybe not as much a swooshing noise as a cavitaion noise. It almost seems like there's alot of air under the transom and that makes the props sound wacky.

[TwinFin]

can't speculate on the noise you describe.
"soft" hydraulic throttles make me wonder if your lines might need to be bled to remove air?
I have 300's - I don't notice any hesitation during throttle-up. I've been told to bring the throttles up quickly. I run her up to 3100 or so and then back off if it's too rough to run that fast.