Ok so I just installed a manual jack plate (6” setback) on my boat. It’s an 18’ Skeeter with a 90hp engine. The only reason for the install was fishing shallow water. The first time on the water with it I could NOT get it up in plane! It would point straight toward the sky and never sit down. Before I installed it I never once had an issue getting on plane. Unfortunately I was fishing a tournament so I didn’t won’t to waste time tinkering with it and besides that I really wasn’t sure what way to go with it. I’m going to call the dealer that installed it tomorrow and find out what I should do but in the mean time I’m needing some answers! haha So if anybody has any suggestions or know whats going on please let me know. Thanks. 

Did you trim the engine all the way in towards the hull to take off.  If so you just might have to adjust the height of the jack plate up or down and then lock in position.  Test run it and come back and adjust again.

Thanks man. I did have it trimmed all the way down. Any idea which way it should go? Up or down? 

Usually about 3.5 inches from the prop shaft to the bottom of the pad is about right for mine but I'm sure all are going to vary some depending on the HP, prop ect.

 But man, a manual to get into shallow water is way more work than I would want .

A manual plate is supposed to be a set it and forget it installation.  You get more speed by moving your motor back out of the turbulent water created by your hull.  You may gain a little reduced plain time but normally a plate does not help in shallow water.  Your only adjustment is with your trim/tilt.  Now a Hydrolic plate will allow you to raise the entire motor up when in skinny water.  I have a 6 inch hydrolic plate on my 21 foot Ranger.  I can get on plane in 3 feet if I raise the plate up.  If you want to get to plane faster in skinny water you are going to need to go to a hydrolic plate, trim tabs or a whale tail on your motor.  If it were me I would go the whale tail route with a good unit from a custom manufacturer.  Then you can set your plate where it needs to be and get the benefit of the plate and the whale tail will help you in shallow water.  As for setting your plate you need to start at 3.5 as has been said and raise it in small increments to get the best performance.  

Thanks for the info guys. 

3 1/2" to the centerline of the prop shaft to the bottom of the center of the pad with the prop shaft level with the pad surface is standard engine height.

90 HP on a 18' Skeeter glass bass boat is way under powered IMO. My SF175 18' Skeeter ran a 200 hp for reference.

The Jack plate will change the fulcrum point to increase bow lift.

Tom