Jack Plate position ??

[Hawgwild]

I have a 2009 Triton TR186 with a 150 Optimax and a 10" jackplate....that motor is max hp for the boat..

Prop on motor is a Mercury Marine Tempest prop...24 pitch...thinking of going to the Fury prop in the future but current prop is still in very good shape with only a few small nicks

I take off and get on plane pretty quick when the livewell is empty...pops right up... but when I have a full livewell the boat "plows" the water a good bit before it gets on plane...even worse if I have a passenger in the boat...

I do trim the motor all the way down when I take off...

I not too concerned about speed but if I lower the jackplate some will that help me get on plane a little faster without plowing so much water...

Thanks for any advice...

[Ron Fogelson]

Scottie I know all boats are different but I always trim all the way down before taking off than as the boat starts to get on pad I'll trim up as I gain rpms & speed.

Adjusting your motor a 1/4 can make a lot of difference in hole shot, handling and top end, typically dropping a motor will help gain hole shot, but if you are not red lining your rpm's now you might gain over all performance with a 23 pitch tempest or if you are close or over your rpm max a 24 furry might be a better option.

[Hawgwild]

Thanks Ron...I'll lower it down 1/4' at a time and see what happens...looking good this week so hopefully will be on the lake a couple of days..

..might try a 23p also...

Thanks for the info..

[BassBUFF]

Make a mark on the jackplate BEFORE you move it so you can always go back .

I'd also like to know what the prop to pad measurement is right now so folks can have a better idea of advice to give you Scotty.

[Hawgwild]

Make a mark on the jackplate BEFORE you move it so you can always go back .

I'd also like to know what the prop to pad measurement is right now so folks can have a better idea of advice to give you Scotty.

Just made some measurements..

From the top of the prop shaft to pad is about 3 1/2 inches.
From center of prop shaft shaft to pad is about 5 1/2 inches.

If you rotated the prop with one of the blades up, the tip if that blade is actually above the pad about 2 inches..

[-Joe-]

I thought I went to the extreme putting a 10" JP on a TR19, think you have me beat with yours. Our Tritons like the motor to run high. 2 1/2" below pad is the usual magic number to start with. At that height you will need to run it and good up some numbers to know which way to tweek it. Like Ron said, a 1/4" will make or break your set-up. We need to know your water pressure and RPM at WOT. That will tell us weather to go up or down or prop change. With 10" of set back, you should have taken just about all the Chinewalk out of the equation. I know on mine it did and I can run mid 70's with no problem on my 200 3.0 Liter. With the right set-up you should get 63-65 with now problem.

[BassBUFF]

Scotty if you're centerline is 5.5" below the pad then you're waay to low for a Triton!

[-Joe-]

[Hawgwild]

Well dang....I've already lowered it a little over 1/2 inch.....Heading to the lake tomorrow so will see how that does....then might raise it above were it was if this don't help..

[BassBUFF]

Great diagram -joe-!

Is this how you measures it Scotty?

[Hawgwild]

Great diagram -joe-!

Is this how you measures it Scotty?

Correct....I had about a 6' stick that I could wedge between the pad and back roller and stayed flush with the pad.... It extended past the prop...and I took my measurements that way...not exact but close..

I was on Caddo today and it seemed to help a little since I've lowered the motor...still not on plane as fast as I would like with a full livewell but that might be something I just might have to live with..

Guess the only way to really tell would be to move it above the original mark and see what happens....Probably go back out Thursday and try like that....

BTW: Caught one good keeper and 2 slots up Jeems today....

[-Joe-]

Another idea to think about would be to get a hole shot plate. I had a big issue after adding the 10" JP was the azz end sitting down on take off causing water to gush up through the JP, thus inturn causing resistance. I had a machine shop make mine out of 1/4" Aluminum plate and it works like a charm.
Did you by chance get any WOT numbers while you were out?
Also when I get home this evening I will measure a few things on mine because some of the measurements in your earlier post seems odd. One being the term 'prop shaft' You indicated 3 1/2" to the top and 5 1/2" to center. What exactly are your calling the prop shaft? The shaft normally refers to the shaft the prop itself mounts to, its only like 1" in diameter. Also you said if you turn the prop to have an ear pointing upwards then it is approx. 2" higher than the pad. Seems like if it was that high then you would be closer to 3" or so below pad on the set-up.
Oh yeah..congrats on the fish, I went out Sunday and stuck out!

[Hawgwild]

Did you by chance get any WOT numbers while you were out?
Also when I get home this evening I will measure a few things on mine because some of the measurements in your earlier post seems odd. One being the term 'prop shaft'
Oh yeah..congrats on the fish, I went out Sunday and stuck out!

I'll have to recheck WOT numbers when I go back out but seem like I was doing around 5300 or 5400 rpm wide open and trimmed up...don't think I've ever seen it much higher that that....dang water pressure guage doesn't work though..

Maybe I'm doing this all wrong....so I took a picture...the stick is wedged between pad on boat and last roller on trailer and I put a level on it so it's pretty much straight out from the bottom of pad...

If I'm doing this right them my original numbers were a little off but not by much...looking at that picture I got about 5 3/4" from that black spot on the propeller and the top of that stick....motor is somewhat straight up and down..

BTW: I don't have a 10" jackplate...it is a 6" jackplate...my bad..

[-Joe-]

Not the way that I set mine to measure it but not sure that you won't get the same results your way. I pull mine up on a level concrete pad and lay under mine with a 4' level against the center of the pad and have someone raise and lower the hitch jack until its level. Then I will trim motor until cavatation plate is level. Then measure the two and subtract for the below pad measurement.
With the pic you have, I will still say you are way low. Also at 5300-5400 WOT you are either way over propped that I don't believe or in way too deep of water. I would definately go with the latter. Meaning to go way up on JP. The WOT RPM for that Opti should be around 5800 RPM. The only thing bothering me is the WP gauge not working because that will tell you when to quit raising the motor. Merc say 15 PSI, I like 18 because you will loose some in turns.
Also I am running a 4 blade Trophy Plus which helped tremendously on the hole shot.

[BassBUFF]

I agree with -joe-, you're too low. But I also think your measurement is off due to the angle the motor is sitting versus the boat. Take a measurement using -joe-'s method and I'll be it's closer to 4". Still way too low. I'd say give it a shot at 3.25" below pad and start making 1/4 changes up until you gain rpm without gaining speed, then go down 1/4". Now this all assumes your water pressure stays good. Isn't it still under warranty??

[Mr. bigmouth]

scottie you can adjust the plugs in your prop for better holeshot....judging by your picture i would say u need to get plugs with bigger holes in them.....u can adjust until u get about 3500 to 4000rpm on initial holeshot with the throttle dumped wide open.....just a thought .




Jerry

[Hawgwild]

OK...Back on the water today and definitely have gone to high with it....

Used Joe's method and leveled trailer and motor, took measurements then subtracted...Centerline of prop was 3 1/4 inches below pad and definitely too high.....ran OK but wouldn't really "lift" the front end up as much and plane like it has...could only get about 5200 at WOT and I know I was getting more that that before...

So will move it back down probably 1/2 inch which would still be above my original settings before I started this....sure moves down a whole lot easier than moving up...ha

Might have to run back to the lake again tomorrow catch more fish......I mean to test new setting... ....fishing was super today and easily boated over 20 fish...best was a 19" over with many solid keepers and slots....mostly on traps..

[2007nitro901]

Jerry has the correct answer. that is what the plugs are for. lets exhaust around the propeller so there is less pressure on the prop. and yes you will need to set the hight for correct operation.

[drfish]

Almost every tr-186 will be setup with a 6" jackplate, 23" tempest+ prop.  This boat will literally JUMP out of the hole when there is a very light load.  Full load, heavy fuel and full livewells, you're doing good if you can get on plane without your passenger having to lean up on the front deck.  Get your h2o pressure gauge fixed and start about 3" below pad.  Move the engine up until the pressure drops below 12 or the speed drops off.  Readjust to a min of 12psi water pressure and you're good to go.  Expect about 54-5500 rpm with the 23" prop, 59-62mph.  You may also be able to boost your loaded holeshot some by playing with the prop plugs.

(Please fix that pressure gauge asap.  You're playing with fire adjusting engine heights without knowing the water pressure.)