I have an'02 Tiger, 575SC's, with a curved notched transom. See picture.

After getting the boat on plane, I constantly have to work the throttles to keep the engines in sync. I usually do this by listening to the engine harmonics and looking at the tachs. It seems that once I get the engines in sync and have the slightest movement (or tilt side to side) right or left, one of the engines will gain rpm anywhere from 100 to 400 rpm. Depends on which way the boat leans as to what engine gains rpm.

My first thought was to call Throttle UP and work with them on different props. However, I'm not sure that it is prop related because at WOT I'm getting 86-87 mph on GPS running in fresh water; which is normal for this set up. I believe some of you have seen faster speeds in salt water.

I was wondering if the curved notched transom as opposed to a straight notch transom was causing water turbulence or interrupted flow around the props to cause prop slippage?? I've notice the newer Cig models have a straight notched transom.

Any of you out there experience this? Or, by chance is this characteristic normal? Any thoughts from anyone?

what lowers do u have, and what speeds dose this happen?

I have Bravo XR's with a low to average X Dimension.

The inballance starts happening at 45-50 mph (3500-4000 rpm) all the way to WOT.

??? well i guess neither of those two are your problem!It looks like you X is low enough not to interfear with th props. I wouldnt cancel out the prop idea! atleast give it a try.

f129, thanks for your replies. I was just trying to get some thoughts on the issue before I talk to the pros this spring.

Thanks.

Where are you running your trim when this happens?

90% of the time both trim and tab positions are neutral. I have the positions marked on the gauge so this can be obtained while running the boat. If I over trim, the boat will sometimes porpoise so I try not to over trim. Plus, at neutral, I can reach optimum speed at WOT. Granted, I'm on a smooth lake with very little chop.

My best guess is that this issue is prop slip.

Show some pics of the whole boat while you are at it. Can't help you on the rpm changes, but sure sounds like a nice rig.

Lonestar

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Thanks.. and yes, all Cigs are nice especially what is coming out of the factory now.......
Enjoy.... I am!