Crabba

Water over transom

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Have a 14ft Polar Craft with 20hp Tohatsu on it. When cruising at full throttle water comes over the transom. Not a lot but enough to be an issue if run for any length of time. Should an adjustment on the tilt pin fix the problem? More weight in the bow? Right now the pin is in 2nd slot from bottom. 20200710_082915.jpg.c79a216f723db7f2db14211700b20bcb.jpg

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Can  assume you are up on a plane when this happens?  The motor cavitation plate should be about level with the bottom of the  transom. Is it motor prop spray you are seeing?

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What John is trying to say that is that it sounds like your motor is mounted too low.  Cav plate should be at, even maybe up to an inch higher than keel - put a straight edge on keel and show us where it hits the motor

 

Do you experience any porpoising at speed?

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43 mins ago, John P said:

Can  assume you are up on a plane when this happens?  The motor cavitation plate should be about level with the bottom of the  transom. Is it motor prop spray you are seeing?

Yes when on plane. The wash between motor and transom bubbles up and enters right underneath engine mount.

18 mins ago, makorider said:

What John is trying to say that is that it sounds like your motor is mounted too low.  Cav plate should be at, even maybe up to an inch higher than keel - put a straight edge on keel and show us where it hits the motor

 

Do you experience any porpoising at speed?

No porpoising. Measures about 1.5 inches. Straight edge to plate20200710_103150.jpg.9eb38e944172af2a1016311cb4da2dca.jpg

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Posted (edited) · Report post

20200710_112035.jpg.5f05e5d2d7109a0adca1b62e9b75dd01.jpgOk. Sorry for confusion. Above measurements are whacked. Watched some vids using what ya'll said and I think I see what your saying. Ran a straightedge from cav plate to hull and it hit about a half inch higher than hull. So if I raise it up so it runs straight with hull this might set me up right? 

Edited by Crabba

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It is definately low.  Too low.

 

Raise it.  Having the plate a hiar higher probably wouldn't hurt.

 

From what I see, you don't have slots in the bracket, only holes?

 

 

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44 mins ago, makorider said:

It is definately low.  Too low.

 

Raise it.  Having the plate a hiar higher probably wouldn't hurt.

 

From what I see, you don't have slots in the bracket, only holes?

 

 

Thanks. Yes only holes. I went up 2 positions from where I started. Seems to run more level to the keel now. I'll run that and test it out

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Ok so obviously I'm new with this lingo. Just so I'm clear. Here is eye level of where it sits20200710_125402.jpg.7f6d1322db7cad5a45c34ce2491eb479.jpg

Here is how it's mounted on boat.20200710_125327.jpg.d6efd86f375b5b64af5514744c0f96a5.jpg

Not much room to go higher to raise that plate. I only adjusted the pin that seemed to level it off not really raising it though. If ya'll are saying that the plate needs to be higher, is there a way to space up the motor on transom to raise the plate? 

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Posted (edited) · Report post

Most definately has to come up a couple of inches.  Don't worry about the clamps.  Use the bolt holes.  Looks like you will be drilling some holes.  Trim pin will do nothing for you.

 

I would drill one set of holes and test it.  If running better, drill additional holes and use all 4, don't worry about the clamps.  I would overdrill the holes and epoxy in pvc pipe of the appropriate ID to accomodate the bolts.  Others will tell you to use 4200 or 5200, but I think its better to do it correctly, and will make it easier if you ever want to pull the motor for some reason.

 

Based on the first pic, you may have to put a shim of equivalent thickness of the transom cap overhang between the bracket and transom so that she sits flush.  I would use PVC board or some kind of plastic, but it doesnt much matter.

Edited by makorider

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