Help raising engine for new prop

[Wee Hooker]

Per an earlier thread /suggestion I've bought a new (11x 103/8") Turning Point Rascal and hub to replace the factory (9.9x10) prop on my new 30hp Nissan 4 stroke. Here's the issue.
As you can see, by the first pic, my cavitation plate is a good 1.5" below the keel so no doubt, the motor can come up. Also at the suggestion of this forum, I've agreed that I should raise my engine first THEN swap props. However, as you can see from the second pic, the motor bracket is shaped so it now fits neatly around the transom cap. If I want to bring the engine up ( say 2 holes) the mount is going to contact/crush the edge of the cap ( across a 14" area) and give me uneven contact with the transom. ( Not to mention create a potential leak point on the transom.) So how do I handle this? Make a 1/16" aluminum/poly shim to fit under the whole bracket?

Lastly, when I raise the motor, I won't be able to tighten the two clamp bolts on the front of the transom. I'm guessing I don't need these since it's got 4, 1/2" through bolts but I hate to loose the security. All thoughts welcome. I'm starting to lean towards leaving well enough alone.

BTW/FWIW, Got 30 mph on the gps with the factory prop as is.

 

[coastalcruiser]

Re: Help raising engine for new prop

ohh i see the problem you have a walmart ruler

 

[Silvertip]

Re: Help raising engine for new prop

You can buy aluminum plate at many home improvement stores to shim the motor so it doesn't crush the cap. You have four bolts holding the motor to the transom. You don't need the transom clamp bolts. Those same four bolts hold lots bigger engines than yours. You should however be using nylon insert (self locking) nuts rather than standard nuts. You also don't have any lock washers but those wouldn't be needed with the self lockers.

 

[steelespike]

Re: Help raising engine for new prop

I think you mean a 10 3/8 X 11 prop. (diameter X pitch).Was the old prop over reving?You wouldn't normally initually increase pitch unless you had an over reving problem.Perhaps the 11 was all that was available?
Would be nice if you could raise it to a point just before venting becomes a problem.Most motors end up with the plate up to an inch above the bottom.
As long as you have the Turning point put it on and test then try raising the motor.The turningpoint will allow a maximum height.With minipulation of the bolts it appears you could gain over 2 inches.This could net a couple of mph.
or more.

 

[Wee Hooker]

Re: Help raising engine for new prop

Actually the factory 10P prop reved @ 6180 (max on motor is 6250) so it was perfect. I need a spare prop ( for remote area fishing) and the turning point was a) recommended b) cheap. The lowest pitch TP makes for the motor was a 11P so I figured I'd try it. If it's not perfect, the TP will become the spare.
Motor height bothers me regardless. I'm going to have to ( at some point this year) make a 15 x12" shim to raise it up at least 2 holes.

 

[steelespike]

Re: Help raising engine for new prop

If you have a really good prop shop they can repitch or soften the cup on the Turning Point if necessary.
Looks to me you may be able to add just a strip the length of the bolt flange.Thats probably all that contacts the transom.If you raise the bolts you could seal the strip and old holes.I would clamp strip in place and drill for the bolts just let the flange and bolts hold it in place.