I installed a CMC trim/tilt on my '76 85hp at the end of last season. I only ran it once breifly before winterizing. Unfortunately, while I now had the ability to trim the motor, my boat was porpoising and I subesequently didn't see much, if any, performance improvement. In fact it was a bit of a let down, after doing what I thought was a nice installation job. Anyway... I'm thinking the setback may have something to do with it. This unit sets back the motor probably about 6". I set the motor at approximately the same height as it was when it was directly mounted to the transom. Should I possibly raise it higher? Or shoud I just add a hydrofoil? My rig would do 39mph (GPS) maximum last year. This year, I'm determined to break the 40mph barrier. So, any advice is greatly appreciated.
Forget the hydrofoil.Setback applications require some tweaking.By setting the engine back 6" you have effectively changed the center of gravity (CG) point of your rig. That means weight distribution.You are transom heavy, now.Move anything you can forward.Once you accomplish that, you can experiment with moving the engine up, at small increments.