Fixed jack playe

[Dtk15c]

Ive got a 79 glascraf 18 with a 86 Johnson 90. It has never hopped up on plane but it got up eventually no matter the weight. I installed a fixed jack plate (4in up, 4 in back) to try and get the height of the motor right on the boat and now if I have any more of a load then just me it will not get on plane. Here is a picture before the fixed plate. I'm not sure if the motor is getting to the time where it's gonna need a rebuild or the weight is to far back or to high. Any help or advice would be great. Ran 32mph before plate and 27 with just me in it.


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[Dtk15c]

Here's how it is now.


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[Steve Stinson]

You have it too high on the transom. The cavity in front of the motor is not a true tunnel. It does not go far enough forward to let your prop get enough water when the boat is in motion. You can leave the motor set back from the transom, but you are going to have to drop it down until the flat plate on the foot, just above the prop is even with the bottom of your hull. (The actual hull bottom, not the top of the cavity).

A better cure for the problems you are describing would be trim tabs.

- Steve Stinson

[Dtk15c]

Thanks for the help I will have to pull the plate off! So it was about the right height before the plate? That is the lowest it can go on the plate.


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[DAWG FAN]

Checkout Smart Tabs. Cheap, easy install and work great.

[Steve Stinson]

It looks like the engine height was about right in the top picture, before the installation of the jack plate.

I would have to see it in person to know for sure, but guessing by the pics - it appears that the only way to drop the engine down some is to either

A. Re-install the jack plate lower or remove the motor

or

B. Cut the top of the jack plate off and drill new holes for the motor bolts.

Steve Stinson

[dombern34]

by looking at your pictures, it doesn't seem like your "jackplate" moved the motor UP much at all, now when I had my tunnel hull I was having a prop issue, maybe yours is slipping too much at the beginning and you're not getting your desired hole shot, try a four blade prop. good luck

[Dtk15c]

In that picture it is as low as it can go on the plate. I'm gonna remove it and see if it gets up how it should or if I need to find out what's wrong with the motor.


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[leonreno]

Run a compression check on the motor, that would be the first step in checking condition of motor.

[Dtk15c]

That's on the list next time I go home I'm gonna bring it back to school with me


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