1st time Jet Boater. 2019 SX190 Cavitation?

[Mattnorton520]

First of all, this is an incredible platform. What a wealth of knowledge and user experience.

I impulse purchased a 2019 SX190 about 3 weeks ago (July 4th) and I’ve spent more time searching and browsing on here than I’d like to admit.

Down to it: We (Family of 5) took out our new to us boat out the weekend of the 4th and had an absolute blast. That being said, I think I’ve got some cavitation issues. The boat is stock as a rock. Right at 80 hours. Fresh service prior to my purchasing (new plugs, oil change, nothing extensive).

I may be making something of nothing but again this is my first time in a jet boat and I’m not sure what is normal? (I’m trying to keep this short)..

I’m going to attempt adding a few pictures I’ve taken of the impeller and intake grate area as well as the twist in clean out inspection port plug. I have a suspension (thanks to you guys) that my intake area needs to be re sealed. The impeller looks pretty good to me? I am getting water on top of the twist in inspection clean out port plug (idk what to call that thing) and I’m suspicious of the rubber gasket allowing water upward and past during the cavitation. The hole is completely full after boating.

In short, here’s some pictures. You guys tell me if you see some cause for concern!

I’m all in on the L13 cone, ribbon delete, etc. but first want to do the “cheap stuff”. Thanks in advance!

If I did this post wrong, I’m sorry.

 

[sunbyrned]

Do you feel the cavitation (rough vibration) or just suspect it because if the water on top? Water on top is normal.

 

[Mattnorton520]

Do you feel the cavitation (rough vibration) or just suspect it because if the water on top? Water on top is normal.

From a no wake speed to WOT it’s quite noticeable. I’ll back off WOT and easy in and it catches up.

Taking turns at 30 ish mph seems to knock quite a bit off as well. But mostly the “holeshot” is where it is noticed.

I’ve read on here about how it’s normal for water on top, but the pictured gasket looks pretty rough. I wonder if it is serviceable?

Thank you for your reply!

 

[Babin Farms]

When you say “noticeable” what are you hearing or feeling? When I feel cavitation the whole boat has a vibration and my passengers will notice.

 

[Mattnorton520]

When you say “noticeable” what are you hearing or feeling? When I feel cavitation the whole boat has a vibration and my passengers will notice.

Maybe idk what cavitation is..
Best thing I can compare it to is no traction? Like if you floor it in a fast car and don’t go anywhere. No noticeable vibrations or rattles or anything. Just pegs the rpms like a clutch slipping? I hope that makes sense!

 

[FSH 210 Sport]

First off, you get a HUGE gold star and an evening in the corner of excellence for posting copious pictures of the problem and suspected problem area’s in addition to a full description of your purchase and a ride report. That is HUGE! A lot of times we need to drag the info out of people. So you made it pretty easy for use to help you.

I would ask these questions of you;
-Do you see any radial scoring on the wear ring opposite where the impeller spins? It looks really good from here but you can get a better look with a bright lite and closer inspection.
-What altitude and temp are you boating at?
-What was the maximum rpms you observed?
-How many hours are on the boat?
-Are you boating in Salt or Fresh water?

Your impeller looks pretty darn good, there are a few dings in the leading edge of one of the blades so some rocks must have gotten sucked up at some point. The gap between the impeller and the wear ring also looks good, the gap should be .014”-.01177” at least that is what my service manual shows, and on that subject get yourself a service manual, they are super helpful to have. If you need help getting one let us know and we will post up the link.

The clean out plug seal needs replacing so go ahead and order up one of those. Get an OEM one.

@Spooky pantz has some O rings for sale that you put down into the clean out plug area that completely seals up the plug well and keeps it dry.

S

Boat Stuff Thread 'O-Rings for Clean-Out Plug'

Jul 7, 2025

O-rings to help seal the clean-out plug(s) and prevent water from sliding past the plug. On my boat, I found that my plug was always full of water and may have been overflowing into the inspection tray. Thanks to @TeeNGee, who found that this O-ring could help better seal the plug and prevent water intrusion (Thread). Since installing this O-ring, my plugs are bone dry.

These aren’t super easy to find/buy so I bought them in bulk. I now have a BUNCH to move

$5 each, shipped to CONUS via USPS. You’ll need 1 per plug

• Spooky pantz
• Replies: 5
• Forum: Classified Ads

Thread 'Another Clean-Out Plug Thread'

Nov 20, 2023

There has been lots of discussion about water on top of the clean-out plugs and that its fairly normal. Many people believe that water gets into the inspection port area from the swim platform when stopping, etc. and it fills the clean-out access tube.

I used to subscribe to that theory as well.... until I purchased the 275SD. The inspection access covers and clean-out ports sit pretty high up off the swim-platform. You would need to stop dead from 50mph or have a 3 foot wave come over the back of the boat to get water on top of the clean-out plugs. When I first started using the boat I...

• Judge
• Replies: 184
• Forum: General Discussion

• 
• 

The new seals and the O rings will go a long way to keeping water out of the bilge of your boat as well.


Having some cavitation with a full boat load of people, fuel and gear, going from idle ahead and slamming the throttle to WFO is going to happen. As you noticed, if you roll into the throttle, even quickly it won’t cavitate. If you really want to cure any cavitation problem going forward get one of these.

Post in thread 'Leading Edge Twin Impellers: Review Thread'

Jun 6, 2025

interesting info on the leading edge impeller.. am considering one myself.. am really interested if you still have water up your clean out.. if the impeller is loading the intake before the jet ring then pressure may be forcing water up the clean out, and I don’t think that is good at all.. please update

With the addition of the O ring all water intrusion into the clean out well has been eliminated and that has been confirmed by several people. You can read about it in this thread Another Clean-Out Plug Thread

I see you posted there on the last page, go back one page and...

• FSH 210 Sport

I spoke with Dave at Leading Edge Impellers and he mentioned how the twin screw impellers seems to keep the speed bleed off to a minimum in turns, of course if you throw it full port or starboard the speed will bleed off. Both Leading Edge and Impros offer twin screw impellers. The front screw is called an inducer, Skat Trak pioneered this I believe, and this is a great way to get cavitation free operation. Nothing is more underrated that a properly set up impeller and more overrated that doing engine mods via a tuner. I’ve tested numerous sets of impellers and I can say with 100% confidence that if you get a good non cavitating impeller in your boat it will cut the perceived noise by half or 3DB. You can load a db meter on your phone and take before and after readings of the DB’s on your boat at various speeds / rpms.

So check the gap of your impeller to the wear ring and see if it’s within spec, if not you will need to either have your impeller repaired or get a new one. If it was me, and its boating season, I’d get a new impeller from Leading Edge or Impros, AND tell them what altitude you are at as well as the boat information. If the spec is good, you’re good to go.

Get a new clean out plug seal kit, and order a set of O rings from @Spooky pantz to get that clean out plug all sealed up.

Then go out and have some fun! If you are still getting too much cavitation then go to Leading Edge or Impros and get a twin screw. But if the cav isn’t too much then go and have fun with your impulse buy and burn a lot of fuel and put on a lot of hours.

 

[FSH 210 Sport]

If you’re at or near sea level that motor is making roughly 250 hp, but unless you get that impeller to bite there is no reason to go for more power.

If you want to check for a quick performance gain, make sure your air box is very clean and the next time you go out make a couple of passes at WFO and see what the rpms are, then pull the air filter element and make the same two passes, if you pick up some rpm then put the paper elements back in and you can buy the RIVA K&N style air filter and its like having no filter elements installed.

I’m not sure about this next one but perhaps one of the other 190 owners will chime in, I think on the older super charged motors they could benefit from a larger CAC / charge air cooler as I’ve read about heat soak affecting performance, that happens on normally aspirated boats as well. But if the CAC isn’t cooling the compressed air enough the IAT / intake air temp sensor and the MAP / manifold absolute pressure sensor will see that as a higher density altitude and pull the fuel back accordingly.

Seems like several guys with the SC engines are also running a BOV or blow off valve, this helps prevent SC sprague clutch damage / failure when the boat catches air and the engine revs to max then when the pump hooks back up it loads up the SC dramatically and breaks the sprague clutch.

 

[Mattnorton520]

I do not see any radial scoring on the wear ring. It all looks pretty nice.
I’m boating in freshwater in Eastern Oklahoma. About 800 feet and water temps in the 80s.
I’ve seen 7800 rpms pretty often.
Around 80 hours on the boat.

In order to check the gap between the impeller and housing, do you remove the intake grates? Just the Allen head bolts and it comes off?

I think I’ve got the service manual here somewhere. I’ll find it.

I’ve reached out to @Spooky pantz via DM to purchase an O-Ring.

Is there a good place to buy the rebuild kit? Link?

The Leading Edge Twin Impeller looks pretty awesome. Seriously considering it. Where is the best impeller replacement video out there?

Thanks again guys!

 

[FSH 210 Sport]

Okay so you’re reaching max rpms which is great!

To check the gap on the impeller to wear ring you’d just pull the pump out, pretty easy to do, check the service manual for instructions and materials and tools.

To get the clean out plug seal repair kit just go to a dealer’s web site, or call one in your area. I’m not a huge fan of partszilla, some folks have great luck with them, I have not. I have had luck with Babbitts online, just be sure when you order something they have it in stock before you place the order.

Item number 15

https://www.babbittsonline.com/oemparts/a/yam/5b968f6487a86610c06846c4/jet-unit-4

There are several jet pump pull threads.. @Leojay made a good one and is posted here;

Thread 'MUST WATCH - THE ULTIMATE JET PUMP PULL'

Mar 6, 2021

A MUST WATCH for Jet Boaters...
A solid dose of infotainment..
Laugh, learn, share and subscribe

• Leojay
• Replies: 11
• Forum: General Discussion

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• 
• 

Personally I’d just put in a new clean out seal kit and the O ring and go run it! You may be amazed how much better it runs.. go and enjoy it and work on it later.

 

[Mattnorton520]

Okay so you’re reaching max rpms which is great!

To check the gap on the impeller to wear ring you’d just pull the pump out, pretty easy to do, check the service manual for instructions and materials and tools.

To get the clean out plug seal repair kit just go to a dealer’s web site, or call one in your area. I’m not a huge fan of partszilla, some folks have great luck with them, I have not. I have had luck with Babbitts online, just be sure when you order something they have it in stock before you place the order.

Item number 15

https://www.babbittsonline.com/oemparts/a/yam/5b968f6487a86610c06846c4/jet-unit-4

There are several jet pump pull threads.. @Leojay made a good one and is posted here;

Thread 'MUST WATCH - THE ULTIMATE JET PUMP PULL'

Mar 6, 2021

A MUST WATCH for Jet Boaters...
A solid dose of infotainment..
Laugh, learn, share and subscribe

• Leojay
• Replies: 11
• Forum: General Discussion

• 
• 
• 

Personally I’d just put in a new clean out seal kit and the O ring and go run it! You may be amazed how much better it runs.. go and enjoy it and work on it later.

That’s the plan! Ordered a Yamaha rebuild for the clean out and waiting to hear back on the O-Ring purchase. I will definitely report back. Thank you again!

 

[Neutron]

If you’re at or near sea level that motor is making roughly 250 hp, but unless you get that impeller to bite there is no reason to go for more power.

If you want to check for a quick performance gain, make sure your air box is very clean and the next time you go out make a couple of passes at WFO and see what the rpms are, then pull the air filter element and make the same two passes, if you pick up some rpm then put the paper elements back in and you can buy the RIVA K&N style air filter and its like having no filter elements installed.

I’m not sure about this next one but perhaps one of the other 190 owners will chime in, I think on the older super charged motors they could benefit from a larger CAC / charge air cooler as I’ve read about heat soak affecting performance, that happens on normally aspirated boats as well. But if the CAC isn’t cooling the compressed air enough the IAT / intake air temp sensor and the MAP / manifold absolute pressure sensor will see that as a higher density altitude and pull the fuel back accordingly.

Seems like several guys with the SC engines are also running a BOV or blow off valve, this helps prevent SC sprague clutch damage / failure when the boat catches air and the engine revs to max then when the pump hooks back up it loads up the SC dramatically and breaks the sprague clutch.

His boat is a HO1.8 non supercharged

 

[FSH 210 Sport]

His boat is a HO1.8 non supercharged

Thanks!

 

[Ribs77]

Wait, how can you tell that the clean out plug needs a repair? I wonder if that could be contributing to my cavitation issues... (under heavy load (1,000 lbs. ballast) pulling up surfers)

I'll get a pic next time I'm out. I have the Lucky 13 cone ready to install either way... just waiting on confirmation that the bolts to remove the stock cone are 5mm and that I won't strip them

 

[FSH 210 Sport]

Look at the seal…. It’s got a thick black line that is porous looking.. it’s worn out.

You need to get a set of O rings from @Spooky pantz too.

The next thing you need to get is one of those twin screw impellers and you will no longer have any cavitation.

 

[Ribs77]

Look at the seal…. It’s got a thick black line that is porous looking.. it’s worn out.

You need to get a set of O rings from @Spooky pantz too.

The next thing you need to get is one of those twin screw impellers and you will no longer have any cavitation.

I'd for sure get the twin screw impellers, but I read elsewhere that they impact the surf wake. Is that possible/true? I'll have to dig to find the comment, but another poster said that they can no longer surf ropeless on the wave after installing twin screw.

I've got the wave dialed exactly where I want it at this point - now I just want to reliably be able to get up to speed with a surfer! Hoping the Lucky 13 takes care of that.

 

[FSH 210 Sport]

I'd for sure get the twin screw impellers, but I read elsewhere that they impact the surf wake. Is that possible/true? I'll have to dig to find the comment, but another poster said that they can no longer surf ropeless on the wave after installing twin screw.

I've got the wave dialed exactly where I want it at this point - now I just want to reliably be able to get up to speed with a surfer! Hoping the Lucky 13 takes care of that.

Well @anmut and his report didn’t mention that, I know I read the same report you did.. but @anmut seems very happy with his.

Post in thread 'Leading Edge Twin Impellers: Review Thread'

May 7, 2025

The clean out tray and plugs;
It makes sense there would be pressure / more pressure with an inducer impeller ahead of the main impeller.
Do you have the tray sealed around the perimeter?
I realize the water was or may have been above the mechanical access hatch?
Do you have the hatch riser?
Are the clean out plug seals in good shape? I see your boat is a 2020 model, have you replaced the seals yet? Do you put any wax on the seals?
It sounds as if the drain line could have been clogged, and yes the water will still drain out of the clean out tub if the lower drain is below water, maybe...

• anmut

• 

D

Thread 'Who has experience with twin screw impellers?'

May 16, 2022

Just ordered a twin setup for my sx190 from impros and wanted to see if anyone had any experience running one of these? I primarily want to pull tubers and cruise with adults.

• Dirtymunoz
• Replies: 101
• Forum: General Discussion

 

[Ribs77]

Interesting. Well, I already have the cone so I might as well try that first.

Sorry for the thread hijack and thx for the info! Good luck and congrats on the new boat, OP!

 

[anmut]

Surf wave has been good, engine running at lower RPMs to get to speed, more water in the wave. I'll get pictures next time we're out.