Hello,
I have a 1993 19'3' Intimidator with a 225 Yamaha OX66 VMAX. I'm running a 4 blade 25 pitch Trophy Plus prop with 4 large PVS plugs in it. I have the factory 6" jack plate raised all the way up and have the motor mounted as high as possible on the plate. My prop shaft to pad dimension is about 3.25"-3.5". The boat comes out of the hole fairly decently; the motor immediately revs to approximately 3400 rpm and by 3600 rpm the bow is breaking over. The issue I'm having is on the top end...and I used to have a 206, so I'm used to driving a padded boat and dealing with chine walk. However, with my current Intimidator, I can get it up to approximately 70 at approximately 5700-5800 rpm and then the ass end of the boat just starts skating side to side like crazy. It is beyond chine walk where when it starts, you can make small steering adjustments and correct it.
My 206 had the same manual jack plate with a 200 Merc running a 26 pitch chopper style prop with pretty much the same prop shaft to pad distance. It ran low to mid 70's loaded and the ass end was always stuck like glue...you had to drive it of course, but it never felt out of control or started skating all over the place like my current boat.
Any help or ideas would be much appreciated. I didn't know if it could be an issue with the model prop I'm running. I have read a couple of threads where people said they sent their prop off and had extra cup added to it and that cured the problem. I don't mind sending it to Mark to have it worked or going with one of his RAZR 4's if that will fix my problem. What I don't want to do is buy a new prop and have the same issue. To make matters worse, I can't get it up to top speed to provide accurate numbers to him. Thanks in advance.