karsntrux

I have a 1987 34' SCARAB III, 330 hp 454's, TRS drives with BW velvet drive transmissions, and stern mach driver props. At 2000 rpm my port side free winds like a transmission is slipping, first I thought I spun a prop, but Im told by my prop guy that is impossible with the ones I have. Is it possible the tranny is slipping, or is there something between the tranny and the drive that could be causing this. Any help would be much appriciated. Thanks

Audiofn

probably your tranny is slipping. Putt your dip stick and smell the fluid. It will not take long to make your tranny fluid smell like holly hell. If that is not it then let us know and we can go from there.

Jon

Mbam

As Jon says, only a few seconds of slippage and the fluid is burnt. Am I correct that at 2000 RPM the boat is not on plane yet? Is this a new problem? Does the boat get on plane?

karsntrux

The tranny fluid doesnt smell unusual, and yes the boat isnt on a plane yet. Is there cluthches in those velvet drives like an automatic transmission?

Gary Anderson

Yes there are clutches, but it only takes a few seconds of slipping and they will generally burn up and make the fluis smell burned. They dont get better either. There's a drive plate between the flywheel and tranny, but it's very unlikely there's a problem there.
When you say it spins at 2000 rpm, do you mean it's OK under 2000? Does it seem to catch at rpms over 2000?
Could it be the trannys coming out of forward gear. Check the shifter lever and linkage at the tranny for slop. Or maybe the prop is ventilating or cavitating. Is the prop and drive in good condition?
Gary

JUSTONCE

I'm sure you've already checked this but, how does your wake look? Is you drive trim indicator accurate> My gauge went bad and I was trimmed way up when I though it was in, prop broke loose at about 2500 rpm. I could tell right away that it was a trim issue but with a twin engine bigger boat I think it nay not be as apparent. Sorry prolly a dumb suggestion but

Mbam

I think Gary is on target, sounds like a prop slippage issue. Don't take this wrong, but do you have some seat time in this particular boat?

Wally

iTrader: (1)

My first thought while reading through this was to ask what kind of props you have on this boat? Cleavers by any chance??? I tend to agree with the guys above that it sounds like the props not "biteing" If you throttle down does the boat "catch" so to speak? I had an issue like this before too on my 30' Scarab......gave it gas and one side spun.....let off the throttle and you could feel the boat get a bite and get back on the throttle and no problems popping on plane.....let us know more

karsntrux

No I dont have any seat time in this boat, that is definately not a stupid question. This is my first twin screw. I think you guys are probably right on, one of the drives was not all the way down, linkage problem etc. Im going to try it again this weekend, I had my props balanced and trued, he said one of the blades was 1/2 inch or more out. It could have been a combination of that and operator error, thanks for all your input, Ill let you know how it goes. Thanks again