I Have a 2004 sonic 31ss with twin 496 HO that I recently purchased. I am stepping up from a 25 baja with a single 454. Before I panic I figured I would ask some advice. The sonic does have 4 blade props.......... After lowering the tabs and drives I begin to throttle up..... The ass end of the boat will drop down as I apply throttle..... All of a sudden the RPM's on both motors shoot to 3000 3100 and the boat does not jump up on plain.... It will eventually plain off and then flys like a jet but very very slow getting there. Its almost like when a clutch is going up in a car.... You accelerate and the rpms shoot up but car stays same speed. ANY advice is appreciated.

Thanks Don

Sounds about right....I made just about the same step up going from a single 454 in a baja to a 31 sonic...The Sonic does not even come close to coming up on plane like the old boat did....Coming up on plane or the "hole shot" always seemed to take forever...I sent the blades out to be reworked and it was like night and day coming out of the hole

I think you may get more input on here by other guys with 31 footers...

Your description sounds normal. My only question is, how long in terms of seconds does it take for your boat to get on plane? I've never timed mine, but I'd guess 6 or 7 seconds.

Tabs all the way down? I have had boats that would have a hard time getting on place with tabs full down. Try less tab.

Mine does the same thing, tabs down drives in, key for me is to start lifting the tabs AS SOON as the props start to bite and boat will scoot right up. Owned it for 9 years so I've tried every imaginable combo....adding a touch of cup to the props helped 1000% on planing

Not sure how I was trimmed or how much throttle I was giving here but you can see only a few seconds and I am on plane.....keep in mind she is a 35' w/575sci's.....but it gives a general idea of planing time.....If I hammer the throttles she is up in half the time but that is hard on the drives and I don't like breaking my stuff............

http://www.youtube.com/watch?v=ciMhgEGc_ow

Loop parkway.. lots of L.I. boats on here

Dont use your tabs. I have the same boat with the same motors with 28 bravo's and never use my tabs to get on plane. My boat gets on plane with a little bit more then half throttle. That's with 2-3 people and usually 2/3 tank of fuel.

That is the Loop......

My 31SS has the same power (496 HO's) and I have no problem getting onto plane with the tabs up. The main reason I drop the tabs down is to keep the bow down so I can see what is ahead of me. But the RPMs sound about right, takes about 3,000 before mine will plane out.