Driving tips please?

[501nmc]

Hello everyone... I wanted some driving tips for a skeeter zx 190 with a 175 hpdi. It seems that no matter where I set my jack plate, 5500 rpms is where I get my best speed. I've been driving boats since I was 10 but that doesnt mean I know how to get the most out of them. Prop is a 23 pitch tempest plus that's been worked by Mark. 60 @ 5500 rpms. Ptp anywhere from 3 1/2 to 2 7/8. I like the handling of the boat at 3 1/4, at 2 7/8, the boat will hit 55 or so and the rear end will kick to the left a bit. It will smooth out after that just never had one do that.
Boats I've owned: triton tr17 115 v4 yamaha 58 mph
Express 17 with 90 4 stroke yamaha 45 mph.
I would think I should be getting 65 out of my rig but it hasn't come close. 2 8 foot power poles probably dont help.
Just curious if anyone else has experienced this with a skeeter.

[densik]

The zx190 is a 59 to 61 mph boat. The 175 really doesn't give it anymore performance over the 150.

[rickmb]

I owned a 2012 ZX190 dual console with a 175 HPDI for 6 years. I played around with it when I first got it chasing speed. I tried several props and changed my jackplate constantly looking for speed. On a cold morning I finally got it to 67 with a Turbo TXP 24 somewhere around 5900-6000 rpms. Empty livewells and about 1/4 tank of gas in one tank.
Then the upgrades began....two fish finders on the bow, two at the console, one 8ft Talon, and bigger batteries to run it all. My tackle exploded and every compartment was full.
By myself my speed fell to 64 or 63 depending on the lake and time of year. About 60 with a partner, gas, and full livewells.
My final prop was a Tempest 23 in the summer (for better hole shot) and the Turbo TXP 24 in the winter.
I finally settled by prop to pad at 3 1/2. The handling and rough water ride was better at 3 1/2. At 3 or higher the handling was very tight at high speed.

Balance front to back and left to right is important in this boat. The more weight in the bow the less lift and speed you have. This hull loves bow lift. Of course if you get too much in the back you will be dragging the rear too much.
By myself I usually ran the port tank full and the starboard tank empty. I also mostly used the port livewell. This kept the left/right balance good. When I added the Talon I switched to lithium batteries for the TM. This took over 100 lbs out of the back. You could really notice how high the back end was out of the water. And yes, at high speed the back end does come out a little bit once you are off the running strakes and totally on the pad. It does this on my ZX250 as well.

There are kits you can get to change the reed valves or put shaved heads on to boost performance but I never did these. You can take this motor all the way to about 225 hp. Yamaha also made this block into a 200 hp model as well so it is capable of handling the horsepower. As a two stroke it will make horsepower all the way through the rpm curve.

It is interesting that you only get 5500 RPMs - ideal would be around 5700. The limiter on this motor is 6200. Your prop slip is very low for a 23 pitch prop which means your boat is efficient, you just need more RPMs.
The 175 HPDI is a very good motor. I had 300 trouble-free hours on mine. The gear ratio on this motor is 1.86:1 where as the 150 is 2.0:1. Your get 25 more HP and spin the prop a little faster.
The Power Poles will cost you 1-2 MPH.
Some things that could help:
Re-balance tackle and equipment (I had about 80 lbs of tackle and equipment in mine)
Change to Lithium batteries for the TM
Change all fuel filters
Have fuel injectors serviced
Change sparkplugs
Run through a de-carbon regimen with Seafoam
Try to find some Ethanol free gas

I used Yamaha products exclusively for the oil, Ring Free, and Fuel Stabilizer. After 300 hours my motor still started with the flick of the key.

After I started tournament fishing I quit chasing those last few MPHs. I was never going to out run the big boats so functionality won out over speed.

[Thamelau]

Why did you stop at 2-7/8? I would keep jacking it up and seeing what happens, until your water pressure gets too low (IDK what that is on your motor). I don't think that motor has the low water pick ups like the bigger motors do, so definitely would keep an eye on it.

[rickmb]

Why did you stop at 2-7/8? I would keep jacking it up and seeing what happens, until your water pressure gets too low (IDK what that is on your motor). I don't think that motor has the low water pick ups like the bigger motors do, so definitely would keep an eye on it.

That motor does not have low water pickups. I went to 2 3/4 myself and any little bump I lost water pressure. Also, the steering is so stiff it makes it hard to control.

[Thamelau]

That motor does not have low water pickups. I went to 2 3/4 myself and any little bump I lost water pressure. Also, the steering is so stiff it makes it hard to control.

I gotcha.

[501nmc]

Thanks for the replies. I put carson reeds in it last year. Smoothed the idle considerably. I just got through putting the hydrotech exhaust tuner on it. But havent ran it yet. Probably do heads and maybe the big throttle body. Have to call hydrotech and discuss options.
I moved my soft plastics back from the front compartment to the next one back and the ride was much improved. Probably leave it like that for convenience.
I can turn the 23 5700 in the winter. 50 degree air makes a world of difference in power. Havent figured out the lower rpms yet. May just be I got a motor on the lower part of the hp rating. It's a 2012 with 300 hours on it. I run non ethanol and ring free. Change the blue filter every 50 to 75 hours, lower unit oil and plugs once a year. Changed all the filters last year. The vst screen was like new.
The boat has always kicked a little to the left usually when cruising 45 to 50, just never had a boat to do it. Another thing odd is I can run the same with a partner that I do just by myself. Maybe the conditions were different throughout the day and contributed to it.
I've tried several props on it. The tempest is the best top end prop. I have a 21 pitch txp and a vmax t1 23 pitch. The vmax gives me the best cruise speed but is a little slower out of the hole. 21 txp is good but usually has to be run 1/ to 1/2 inch deeper to get the same effect the tempest gets.
I trim up after I get on plane and just bump it up little by little after that. Usually at top speed, you bump it down just a bit and it will pick up 1/2 mph and usually drop to 5500 rpms. Trim gauge is just a needles width past 3/4. Probably gonna be one of those things where you just set it and go fishing. Quit worrying about speed. Lol

[crank68]

I know this may not make sense but I just set up a Triton for a customer and he had a transducer mounted so low and on the pad it was diverting water from the lower unit....you prolly don’t just throwing it out there...

[501nmc]

That could be a possibility. There's not really a good place to mount a xducer 12 to 14" away from the prop center. I have a small xducer mounted about 10 inches from prop center on the right.

[rickmb]

That could be a possibility. There's not really a good place to mount a xducer 12 to 14" away from the prop center. I have a small xducer mounted about 10 inches from prop center on the right.

I mounted my transducer to the jackplate. When on plane the transducer is out of the water.

https://www.transducershieldandsaver...ry/l-brackets/

Of course you need a transducer mounted in the bilge. You should already have one there. Check how close your Power Poles/Brackets are to the water. They should be out of the water while on plane.

[axis]

On my 08' ZX 190, I have it at 4 dots on the jackplate. This past weekend during a tourn, I was at 60MPH @ 5000-5100 RPM. This is where the boat was when I purchased it.

I did play with it last year, and had raised the motor to different heights. I was able to get around 64MPH @ 5500 RPM. I thought the rough water ride was worse and the Skeeter porpoise got a little worse, so I moved the motor back down to 4 dots.

I believe my prop is a 25M.

[501nmc]

The original xducer was in the bilge (hummingbird) the unit was an older one and wouldnt keep depth at speed. I split the lowrance xducer with the long 2 in 1 mounted on the jackplate and the 2d mounted on the keel. If my memory serves me right... I had the same speeds with and without a xducer mounted externally.
I had a 25m on it originally. I was running 5400 rpms (tach). I installed the lowrance units and linked the one at the console to the motor via nmea 2000 and it showed I was actually running 5200 rpms at 3 1/4 ptp or roughly 7 dots. Steering was horrible at speed. Tried a 23 pitch txp and 24 pitch tempest plus that was bnb'd. 5500 rpms in the winter but holeshot was real slow with 2 ppl. 7 to 10seconds if i remember correctly. 23 pitch saltwater m (bought by mistake) was extremely fast on holeshot 2.5 seconds. But was 2-3 miles slower on top end. 58 i think.
Ran it yesterday after the ht tuner. 5600 rpms and 61.7 mph. Best speed I've had in the summer. 81 degrees with relative humidity 100%. 100 rpm gain and almost 2 mph running with the tip of the 8th dot showing and 22 psi water pressure. Its never gonna be a speed boat, I have no desire to go 80. Lol. I would like upper 60s and an occasional 70.
The porpoising was worse on mine also at a higher height and rough water ride was compromised. 3 1/4 ptp is the best all around for me. I do have a baileys fin on it to help with the porpoising, doesnt get rid of all of it but helps a whole bunch.

[rickmb]

You can play around with numbers here:
https://www.mercuryracing.com/prop-slip-calculator/

On the 175 HPDI the gear ratio is 1.86:1. Prop slip of 10% is about normal for a well setup bass boat. Your limiter is 6200 RPMs.
A 25 pitch will need 6111 RPMs to get you to 70. A 24 will need 6345. I just don't think you will get there from here without major mods to the motor and a bigger wheel. The ZX190 hull just wasn't designed to be fast. I think it's on purpose - can you imagine a 18ft boat that could go 70 with a 175? That boat is also heavy for it's size. Basically the same structure and materials they use in the bigger boats. I think by calculations the transom will support a 250.

Running 5600 with a 24 at 61.7 is right at 10% slip so you are right in there. Prop slip is really just a measure of how efficient your boat is running in relation to the theoretical speed. The theoretical speed with 0% slip is 68 with the same parameters.

You are right about the porpoising. The lower the motor the less it is. I found on mine if I trimmed all the way down while decelerating I could ease into it and keep the balance right. Takes practice. The key is to get the bow to ride on the bow wake so the prop doesn't have to work as hard to hold the bow up. I have to do this with my ZX250 as well. If I get too slow it will bounce then I have to get it back on plane and ease up again. On both my boats I could get down to 20 MPH. Adding cup to the prop will help with bow lift. Adding cup is much like when airplanes use flaps at low speed. Cup also helps with hole shot. The downside is that it will add pitch. Adding more to a 23 will make it a 23 1/2 or maybe even a 24 - your RPMs will go down.

Tuning bass boats and motors is a world of compromise. On my ZX190 I settled into 60MPH with a full load and two people as the best compromise between speed, ride, load, and comfort. I still enjoyed those cool winter days by myself at 64 though.

[501nmc]

Rick, how do you like your 250 compared to you 190? I like my boat but would like a little more storage room. I love the ride of mine when it's set up for it.
I crunch some numbers on that calc all the time. Mainly checking my setup and wishful thinking. Lol. I may have ht do some port work to this one eventually. It's expensive but sometimes a joy to learn about things. A pain to try and set one up for all around performance tho.
I think the zx 20s with the 250s only go to mid 70s. 70 would be dreaming by a long shot. 64.4 was the fastest I've been with a 25m in the late fall. Honestly that fast, if you didnt have a speedo, you wouldn't be able to tell it.
I really liked my triton after the engine mods. Mid range power and torque were crazy for a 115. I hope to get something similar after a few more mods to this one.
Thanks for all the replies everyone.

[kry29]

A 25m should be the prop for that boat. The m series is designed for the smaller hp motors.

[rickmb]

Rick, how do you like your 250 compared to you 190? I like my boat but would like a little more storage room. I love the ride of mine when it's set up for it.
I crunch some numbers on that calc all the time. Mainly checking my setup and wishful thinking. Lol. I may have ht do some port work to this one eventually. It's expensive but sometimes a joy to learn about things. A pain to try and set one up for all around performance tho.
I think the zx 20s with the 250s only go to mid 70s. 70 would be dreaming by a long shot. 64.4 was the fastest I've been with a 25m in the late fall. Honestly that fast, if you didnt have a speedo, you wouldn't be able to tell it.
I really liked my triton after the engine mods. Mid range power and torque were crazy for a 115. I hope to get something similar after a few more mods to this one.
Thanks for all the replies everyone.

They are a different ride for sure. The ZX190 was more of a sports car ride. Nimble and light at the wheel with great acceleration. On the river lakes I fish you have to pass boats a lot and this boat was great at that. I could handle big water with it but it would get rough. The ZX250 is a real Cadillac of a ride. Much softer coming off waves and wakes. At 70 it drives so smooth - I can let go of the wheel, eat a sandwich and enjoy the drive. Much better and confident in rough big water. Both are great fishing as well. The ZX250 is a bit more to handle around docks but I do just fine with it.