Mini Jack Plates

[Bass-A-Holic]

I was recently lookin for parts to increase the proformance of my boat. I have a 85' 14 ft. Sea Nymph powered, by a 85' 15 hp evinrude short-shaft. I was lookin at the mini jack plates that dont have the power trim or tilt, just the plate. The ads on cabelas/basspro both say they will allow the mounting of a long shaft motor to a short shaft transom. My question is, can u use these plates on a short shaft transom and motor w/o messin things up? And what other ways can I increase my boats proformance/top speed?

 

[Silvertip]

Re: Mini Jack Plates

Without some speed and wide open throttle rpm numbers it's anyone's guess as to whether or not the plate will increase top speed. There is a cheaper way to find out. Rent or borrow a GPS. Make some wide open speed runs. Play with the tilt pin until you achieve maximum MPH. Then raise the engine one inch on the transom. Before you do that though, check to see where the AV plate is in relation to the bottom of the boat. If its flush, go ahead and raise the engine an inch. Make sure its secure and then repeat the tests. Keep raising until speed no longer increases. Just make sure you don't lose water pressure. Make 1-inch and 2-inch spacers for the engine to rest on while you tighten it down. Use the 1-inch first, then the 2-inch. You should not have to go any higher than that in my view. Once you have engine height set, then you might think about props but you'll need a tachometer when you start that experimentation. Lastly, you are dealing with 15 HP. How much speed do you really think you can pick up?

 

[Bass-A-Holic]

Re: Mini Jack Plates

Alright I'll have to try that, thanks.

PS. Im not expecting to get tons of speed out of such a small boat. Recently i put decks on the boat, so it is quite a bit heavier,and slower. The problem is that I love the 25 MPH speeds it used to go, so i was looking for a way to get that speed back.

 

[Silvertip]

Re: Mini Jack Plates

Adding weight takes away speed as you found out. Playing with set-up may get some of it back but how much is very questionable. I don't think the jack plate is the answer.

 

[Bass-A-Holic]

Re: Mini Jack Plates

I also looked at solas high thrust 4 blade props, but I'm not sure if my motor will be in the right RPM range once I do get it on. Right now I have a 9.5 x 10 prop on, but i dont have a tachometer, so you really probobly can't tell me much if you don't know how many RPM's I'm running right now, but if you can, please do.

Thanks

 

[Silvertip]

Re: Mini Jack Plates

Props are generally the last thing you play with when attempting to optimize a setup. If you notice other boats with four blade props, they are generally high performance bass boats with high HP engines. You have neither of these. Besides, four blade props generally cost you a little top end but provide better hole shot and bow lift. Spending hard earned cash on a four blade prop is not wise since you have no 'base-line" for comparison. What you've done by adding weight probably cannot be gained back. It's no different than adding another person in the boat. As I said, experiment with engine height and trim setting. Without a tach and method of measuring speed you don't know where the engine is operating or what speed you have. The optimum setup allows maximum speed at whatever the recommended wide open throttle RPM is. For your engine that's probably about 6000 RPM. If you add a tach and the engine runs well below that, you need a prop with less pitch to raise RPM. If the engine is running faster than that, you need a prop with more pitch. If its right at 6000 RPM you have what you have.