189 TRX setup

[bware]

Have a 175 ProXS 4 stroke on a 6” manual jackplate. Ran 61.5mph at 5850 according to tach with full fuel and me alone empty livewell. With another passenger ran 58.5mph at 5250. I’m spinning a 22 Tempest but I haven’t yet measured PTP. I get about 25psi water pressure at WOT. I’m hoping I can keep the 22 Tempest but I’m wondering if anyone here has suggestions for PTP measurements or prop suggestions. I’d like to get more speed but I also think I probably should be running in a little bit higher RPM range.

[273 DC]

I am turning a 21p on my 189 trx and need a higher pitch. Possibly could do some trading if wanting a 21p tempest

[1Holeshot]

I would set PTP at 3.5" below pad and raise jackplate setting 1/4" at a time until speed or water pressure dropped then go down 1/4". If your rpms are below 6000 consider dropping to a 21 P Tempest Plus.

For reference my backup prop is a 22 P Tempest Plus and in ideal conditions running the same weight empty live wells etc. I can hit 70 mph solo at 6000 rpms.

[bware]

I just measured PTP at 4 7/8”. I’ll admit I’m a little hesitant to raise all the way to 3 1/2”, seems like a big difference from the dealer setting. Are you saying propshaft centerline should be 3 1/2” below pad?
Also, what gear ratio do you have? Is it the Torquemaster or the 4.8” lower unit?

[barmour]

On a flatish concrete garage floor, put a good (not the ones the size of your whole pinky) level on the bottom V of the hull and level the hull. Then with level on the motor cav plates just above the prop, lower motor until level. Then measure from bottom of V hull to floor, then measure from center of prop shaft or center of nose cone to floor and subtract nose/prop shaft to floor diff from hull to floor diff and you have the PTP distance. If using a tempest prop, pop out the 2 large vent plugs and leave 1 large or medium plug in. Just go right to 2.5 to 2.75 PTP to start or just wasting time on your triton if using tempest plus (fury or other props maybe 3 to 3 1/4 but not tempest plus). Assuming you have the front nose cone water pickup holes, you will have prop blowout on turns/choppy waves and just go up in rpms with no speed gains before you get anywhere close to low psi water pressure issues at WOT (you need to be at or above 13 psi water psi at 4k rpm min). Your rpms will go up noticeably for each 1/2 inch to raise motor height and will gain speed to a certain extent and once you go to high you'll notice rpm gains, but not top end speed gain or speed loss or water pressure to low issues. You will also "gain" drivability at higher speed ie...less squirreliness at high speed when you get the motor higher. You will get the best rpm, top speed, overall performance, smooth handling with the correct prop and PTP. Your holeshot is mostly vent plugs and prop pitch, not motor PTP. Since your running a 175 hp, you likely won't be able to hit more than 65 mph gps and your hull won't get squirrely until 65 mph unless your prop & PTP is not right, by not right if your PTP is 3.5-4.5 you'll be squirrely and that gets better at 2.5 inch ptp.

My experience from a 2005 TR186 w/175 opti, 89 Ranger 364V w/150efi, and 2018 18 TRX w/200 2stk xs

[ford4wd08]

I'm doing the same testing for my setup currently.

I have a 21 tempest plus and a 6 inch rapid jack.

I'm going to try 2.5-2.75" below pad and see what I get. I also have a new to me 22 tempest thanks to barmour I need to try out soon.

I can hit 60 easily with my 21 tempest now, but I think the motor needs to come up more.

Do you see rooster tails with these hulls and the Mercury 4 Strokes? From what I recall it should be level with the motor right?

[bware]

I'm doing the same testing for my setup currently.

I have a 21 tempest plus and a 6 inch rapid jack.

I'm going to try 2.5-2.75" below pad and see what I get. I also have a new to me 22 tempest thanks to barmour I need to try out soon.

I can hit 60 easily with my 21 tempest now, but I think the motor needs to come up more.

Do you see rooster tails with these hulls and the Mercury 4 Strokes? From what I recall it should be level with the motor right?

At my current setting I have zero rooster. We’ll see what happens after I raise the engine.
Will you report back with your results? I will too with my adjustments. I hope to get out this weekend.

[ford4wd08]

At my current setting I have zero rooster. We’ll see what happens after I raise the engine.
Will you report back with your results? I will too with my adjustments. I hope to get out this weekend.

Yes, I'll report back. Supposed to be rain in the area over the next couple of days, but I'll get tot play with it some this weekend.

[ford4wd08]

Discovered something tonight in the garage. I didn't realize how big these 4 stroke motors are. When I mounted my jack plate I used the same holes that were used with the motor on the boat. There is one more set I can raise my motor.

Right now the highest I can go with my motor on the jack plate is 3" prop to pad. I'm going to try that out this weekend and if I need to go higher, I'll borrow my buddies engine hoist and go up another set of holes. At least there is no sealant involved with these holes! Just a quick raise unbolt and install in new spot.

Just shows how much taller these 4 strokes are vs the older 2 strokes.

[Jimmy3]

FWIW, I have a 2018, 189trx with a 150 Opti set at 3 1/2" below pad on a 6" manual plate spinning a 21" tempest plus. That's as high as I can go and still maintain water pressure due to not having low water pickups. My RPMs vary a bit with load but I'm getting between 5500 and 5600 RPMs and 58mph with a light load and 55/56 mph with a full tank and 2 people. At 2 3/4" below pad, half tank, empty livewells and 1 person I was in the mid 5700s at 59 mph and climbing when water pressure fell from 11-12 psI to 6.

With low water pickups and a 175 I would think you should be seeing 5900-6000 RPMs and 65-66 mph with a 22" tempest around 2 3/4"-3" below pad. At least that's what a guy in I fish against claims his setup is.

[bware]

FWIW, I have a 2018, 189trx with a 150 Opti set at 3 1/2" below pad on a 6" manual plate spinning a 21" tempest plus. That's as high as I can go and still maintain water pressure due to not having low water pickups. My RPMs vary a bit with load but I'm getting between 5500 and 5600 RPMs and 58mph with a light load and 55/56 mph with a full tank and 2 people. At 2 3/4" below pad, half tank, empty livewells and 1 person I was in the mid 5700s at 59 mph and climbing when water pressure fell from 11-12 psI to 6.

With low water pickups and a 175 I would think you should be seeing 5900-6000 RPMs and 65-66 mph with a 22" tempest around 2 3/4"-3" below pad. At least that's what a guy in I fish against claims his setup is.

Thank you for that info. I raised mine a half inch but it’s still at like 4 3/8” below pad. I will test but it seems most are running a lot higher, in that 3” to 3 1/2” range with a Tempest.

[barmour]

Keep in mind I've never tested the 4 strokes but from what I've seen on these threads is the 2 stroke tends to run a higher pitch by 1-2 pitch than the same hp/brand/boat of 4 stroke. I'm not sure if the 4 strokes run higher rpm redline or why this is.

[Riccochet]

Keep raising up 1/4" until water pressure drops off below 12 PSI, then lower it back down 1/4" and leave it there. My boat is older, but it's the same hull. 3.5" P2P is the sweet spot for me. Once you're dialed in on motor height you can start playing with props if you need to.

Dealers set the motor low for several reasons. They don't care about performance and don't want come backs for low water pressure/overheating.

[bware]

I’ve been running this weekend with it set at about 3.5” PTP. With the 22 Tempest I still am only getting around 5550 RPM alone and even less with full live well and a passenger. Water pressure is around 20psi at WOT. These reading are from the stock Veethree gauges. Top speed is 61.5 alone and 57.5 with passenger. I will raise it some more and see what happens. I would like to be running a bit closer to 6000 RPM at WOT but not sure I can get there without a prop change.

[ford4wd08]

I just finally got my motor mounted on the last set of holes. I have it set currently at 2.75" below pad. I'll try to get out and run it this week after work with my 21 tempest and report back.

[ford4wd08]

Was able to run the boat last night at ~2.75" below pad. I can hit 6000 rpms pretty easily now at 60 mph. Hole shot seems to be very good too. I think I'm going to send of my 22 tempest to get it repaired and it will most likely be my all around prop.

[Riccochet]

I'd think you should be hitting low 60's with a 175 and 22P Tempest Plus. I run 56-60 with my 150 and a 21P Tempest Plus.

[ford4wd08]

I'd think you should be hitting low 60's with a 175 and 22P Tempest Plus. I run 56-60 with my 150 and a 21P Tempest Plus.

The above info is with my current 21 tempest.

[bware]

Was able to run the boat last night at ~2.75" below pad. I can hit 6000 rpms pretty easily now at 60 mph. Hole shot seems to be very good too. I think I'm going to send of my 22 tempest to get it repaired and it will most likely be my all around prop.

How was the rest of performance? Any cavitation or blow-out? Water pressure? I ran mine with the 22 Tempest the other day at 3”below by myself and saw 62 mph at 5600-5700. Had 21+ lbs water pressure.
Did you see any reason that you wouldn’t keep it at that 2.75” below setting?

[ford4wd08]

How was the rest of performance? Any cavitation or blow-out? Water pressure? I ran mine with the 22 Tempest the other day at 3”below by myself and saw 62 mph at 5600-5700. Had 21+ lbs water pressure.
Did you see any reason that you wouldn’t keep it at that 2.75” below setting?

Didn't notice any cavitation or blow out. Seemed to run great. I need some more seat time at this setting though.

As far as water PSI, my digital sender has not arrived yet due to an error from Mercury. I was using my vessel view mobile to keep and eye on engine temps. I agree with the low water pickups on the nose cone of the 175 Pro XS 4 stroke, I think you will have handling/drivability issues before you run out of water pressure.