My name is Don. I have a 2004 sonic 31ss with twin 496HO. I am running a 26 lab mirage. After lowing the drives and tabs I begin to give power. The boat will drop down in the ass end to begin taking off. The rpm's will then shoot to 2800 3000 very quickly as I continue to bump the throttles but the boat does not plane off. Almost as if a clutch was going bad in a car. You hit the gas, the car will begin to move and the more gas you give the rpm's go up but car dosent go any faster. The rpm's will remain around 3200 3300 until the boat plains off very slowly. Please Help. Once the boat is on plain it flys but getting up as I'm applying throttle im reving to high. Appreciate the help.

did you just put a drive shower on it sometimes they can cause this problem. and labbed props can cause this also.

and if it was me i would be running 4 blades. that 3 blade may not have enough bite for your boat

It's pretty common for high performance boats. My boat does the exact same thing. The props will ventilate, and slip just like a clutch. They will then begin to bite as you accelerate. This isn't a bad thing, since it can take stress of the drives when getting on plane. My props will spin from about 2500rpm's up to 3000 or so when this happens.



Darrell.

Your blowing threw the props ! Which means you are spinning the props . Your just going to have to learn to work the throttles , when it starts to spin you have to pull back on the sticks until it's up and running. As for the tabs on that boat I would just leave them neutral.

I bought the boat with the drive showers on there. Thanks

x2 on this one. Each boat is a little different on how it likes (or doesn't like) to get up on plane. My outboard is mounted pretty high up on the transom via a jack plate. I can change how easily it comes up on plane by moving it up or down. The further down the prop is, the better the bite it gets because the water is more dense down there. If I leave it up, I can pretty much burn a hole in the water and never come up on plane - which is really bad for the motor. So, I generally ease it up until it bites, then nail it.

Have you tried using your trim tabs when coming up on plane? They can really help here.

Appreciate it. I just remeber when I sea trialed the boat before I bought it that it never did that. It jumped rite up on plane with no problem. When I plane just like you said its almost like the props are spinning and um not moving. Ill play with the throttles this weekend and experiment.

My boat blows out the prop very easy (38 ZR 525 ITS), you just have to get used to giving it some power slowly, when they start to blow out back off the throttle a little and let them bite, then slowly get back on the gas. If you are moving up from a smaller boat with less power, and used to just mashing the throttle, it will take some getting used to. Don't think yours is a stepped hull, but if it is having too much tabs on takeoff can raise the stern and make them blow out easier, so try it with just a little tabs and it may help. On mine if my tabs are down more than 4 it makes planing much tougher. Good luck, enjoy the new boat! You will find this website a wealth of information, welcome aboard!

This is classic large performance V stuff and not unusual in the least.

You'll get more bite from 4 blades, but they will still likely blow out on plane.

Like the other guys say- ease it back when it breaks loose and slowly roll it back on as it starts to bite and you'll be fine.

My single 28 does this as well with an Ilmor 710 and a 4 blade 28.

Uncle Dave