jack plate

[imported_bjs]

i installed a cnc jack plate on my 1998 17 ft triton bass boat with a 120 force motor ive tried a 23 pitch turbo ss prop.could not get 5000 rpm's with the motor raised on the jack plate as high would go.so i raised the motor 1 more hole on the jack plate.that really didnt gain any rpm's either.so i tryed a 22 pitch laser2 ss prop that gained about 100 rpm's.i can only raise the motor 1 more hole on the jack plate do i need to look at maybe a motor problem rather than a differnt prop.can i take the 23 pitch turbo prop and make a 22pitch prop? ialways hear dhadley or wallyhead say not to fix rpm problems with a prop.

 

[cougar1985]

Re: jack plate

michigan wheel prop selector says you should have a 13 x21 ss prop or a 12 3/4 x 21 aul.hope i got that right,you can verify yourself on their site. these props should get you in the ballpark.i think people are misunderstanding the other polsters.differnt boats and their designs require differnt prop selections.i hope this helps. i used a gps also on my boat to get mine right,and belive it or not the combo of tac and gps will help you determine whats best for you.luckily for me i have a lot of props available to me to fool around.

 

[WillyBWright]

Re: jack plate

Do you know if you have a Force gearcase or Mercury? Force's have an exhaust snout out behind the prop. Mercury's is pure thru-hub exhaust and you can play with those more. With the Merc gearcase, you can run a High Five (23 picth guess), plug the top two pairs of water intakes, and jack her way the heck up. Those props can run just above the bullet with the right boat. Translation, the motor can be hung so high that the prop pierces teh water by a few inches with the waterline below the upper two water intake holes. 3-4mph.

 

[cougar1985]

Re: jack plate

i honestly dont think your going to go anywheres till you prop to the right pitch.this is just my opinion but you should not have to jack the motor to the sky to get the right rpms.at least on my boat the jacking did not work and the 19p gave slightly better rpm and more top end than the 21p(for my applicattion).it is certianly worh a try to get a 21p and try it,can you borrow 1 to try?

 

[walleyehed]

Re: jack plate

The higher you can run the engine without losing water pressure...the better it is..<br />To "properly" set one up, you do not start by changing pitch...we maximize the set-up first, whether it be jackplate for heigth and/or setback...both play a role in set-up.<br />When you've maxed out with what you have, then you may need to go to a higher pitch if it's done right. If it's WAY over-propped to start with, your results will be less than acceptable.<br />Changing pitch is the last thing to do to get the R's up, unless, as I said, you're over-propped to begin with and raising up still doesn't get you the R's.<br />Cougar, we raise the engine to get the gearcase (anchor) out of the water a bit.....why have all that drag if it's not needed.

 

[cougar1985]

Re: jack plate

bear with me on this one, but wouldnt hull design play an important part in the equation. id love to keep jacking my motor up if possible but when i did raise it 1 inch it did not change rpm 1 bit atall. how high can you safely go before you have to go to low pick ups ??? i dont want to highjack his post so maybe can be adressed under my post for high rake s/s prop

 

[walleyehed]

Re: jack plate

I'll go to your other thread..

 

[imported_bjs]

Re: jack plate

tirton bass boats like a high motor height.some bass boats dont require a high motor height.i have good water pressure i blocked the top water hole im think im going to raise the motor to the last hole and then if that dont work i will go down 1 pitch.unless everyone thinks thats not the thing to do. yes i would like to have mercs lower water pickup unit my freind has one on a bullet boat but they are high dollar and you have to change the drive shaft to.but that hull is bulit for speed and he has speed 80mph plus ?the jackplate has helped with handling and dirveabilty i love that part of the plate.the ride is a lot smoother.