Cavitation issue

[Dami860]

Hey folks,

Long story short, I hit a shallow area recently and ever since then, I'm getting a cavitation issue around 10-15 mph when I'm WOT. It doesn't happen when I ease the throttle all the way. After doing some research, I'm hoping my only issue might be resealing the intake tunnel. I've posted pics for reference. Any help would be greatly appreciated. I'm prepared to roll my sleeves up if needed but the impeller looked good to me.

 

[2kwik4u]

Impeller looks fine.

Check out this thread. Resealing the pump housing was one of the best things I did to reduce cavitation!

Thread 'Hero or Zero?......"Resealed" my Jet Pump'

May 26, 2018

OK, Where's @swatski and @gmtech16450yz ?!??! I need someone to tell me I didn't just make a ginormous mess out of my pump housing.

Been fighting a cavitation problem under load when tubing. Might be technique on my part, but still bugs me. Put an L13 cone on a few weeks ago, lost some RPM, but still had the cavitation while turning/tubing. Read lots of talk of resealing the pump to keep cavitation at bay. So here's what I did about it.

Picked up some marine sealant. Finding 3M 5200 around here on a Saturday is like pulling teeth. Loctite has a comparable product, so I'm...

• 2kwik4u
• Replies: 28
• Forum: Yamaha AR190/192/195, SX190/192/195

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• 

If you do that, next step would be a Lucky 13 Cone. Expensive, but worth it. Between those two I haven't had cavitation in the pump for years.

 

[Dami860]

Impeller looks fine.

Check out this thread. Resealing the pump housing was one of the best things I did to reduce cavitation!

Thread 'Hero or Zero?......"Resealed" my Jet Pump'

May 26, 2018

OK, Where's @swatski and @gmtech16450yz ?!??! I need someone to tell me I didn't just make a ginormous mess out of my pump housing.

Been fighting a cavitation problem under load when tubing. Might be technique on my part, but still bugs me. Put an L13 cone on a few weeks ago, lost some RPM, but still had the cavitation while turning/tubing. Read lots of talk of resealing the pump to keep cavitation at bay. So here's what I did about it.

Picked up some marine sealant. Finding 3M 5200 around here on a Saturday is like pulling teeth. Loctite has a comparable product, so I'm...

• 2kwik4u
• Replies: 28
• Forum: Yamaha AR190/192/195, SX190/192/195

• 
• 

If you do that, next step would be a Lucky 13 Cone. Expensive, but worth it. Between those two I haven't had cavitation in the pump for years.

Thanks. Yup, that thread is what prompted me to think that's what the issue is. I haven't had cavitation since I've owned it and hit this shallow area.

 

[SamN44]

Thanks. Yup, that thread is what prompted me to think that's what the issue is. I haven't had cavitation since I've owned it and hit this shallow area.

From my understanding, the sleeve is softer than the impeller and is the sacrificial part. So, even though the impeller looks good, you could have gouges in the housing. It doesn't take much to cause cavitation.

 

[Dami860]

From my understanding, the sleeve is softer than the impeller and is the sacrificial part. So, even though the impeller looks good, you could have gouges in the housing. It doesn't take much to cause cavitation.

I resealed underneath and took the pump off but I'm not seeing anything that might be causing my issue. I'm guessing at least having removed it will save me some money if I bring it to the dealer.

 

[SamN44]

I resealed underneath and took the pump off but I'm not seeing anything that might be causing my issue. I'm guessing at least having removed it will save me some money if I bring it to the dealer.

What does the sleeve look like that the impeller is sitting in? Any scratch in the sleeve that can catch your fingernail will cause cavitation. The tolerances for the jet pump to work properly are very very tight.

 

[Dami860]

the sleeve seems ok to me. Oddly there are fingernail catching grooves in the crankshaft. I took some pics where that sits.

 

[Steve73]

I have this same issue on my 2018 AR190. I have to ease into the throttle from 10-15 mph otherwise I cavitate (“spin-my-wheels”). I’d love to know the fix for this issue.

 

[Dami860]

I have this same issue on my 2018 AR190. I have to ease into the throttle from 10-15 mph otherwise I cavitate (“spin-my-wheels”). I’d love to know the fix for this issue.

I've had a lot of people telling me that it's normal. Since I bought this brand new, I know for a fact that's not normal.

 

[2kwik4u]

I've had a lot of people telling me that it's normal. Since I bought this brand new, I know for a fact that's not normal.

Yea, that's not normal at all.

I've had 7 adults aboard and a large cooler in the floor, and still pulled someone up on a wakeboard. Stock impeller, stock wear ring, sealed intake tunnel, Lucky 13 outlet cone with one spacer removed. Only engine mod is a removed spark arrestor (ribbon delete).

Cavitation in pumps (not just jet pumps, all pumps) when one of a few things happens. Either air is introduced to the system on the low pressure side, there isn't enough flow on the low pressure side, or the pump is oversped so significantly that it vaporizes the fluid as the tip of the pump moves through it. 3rd is impossible for us, because the prime mover is an internal combustion engine. So, cavitation comes from either not enough flow on the inlet side, or the introduction of air on the inlet side. Sealing the tunnel prevents air intrusion. That leaves us with just a lack of flow. This can be from poor tunnel shape, obstructions, or "leakage" around the sides of the impeller blades.

Most every case of cavitation I've read here, has been solved with a close look at the intake tunnel, the leading edges of the impeller, and the wear ring. If those are all in good condition, and within factory tolerances, you should be in good shape. Since you've resealed your tunnel, it's time for another water test. Get a cheap set of feeler gauges and check the spacing between the wear ring and the impeller. I think factory spec id 0.030in, but don't quote me. It's in the manual somewhere.

 

[itsdgm]

If I was a betting man (which I am not), But I did once stay at a Holiday Inn Express . I’d say your issue is right here.

I do see that you’ve already sealed it up. Hopefully that fixes the issue. Look for any loose sealant from the intake grate all the way into the pump as well. Sometimes these intermittent issues come and go if the sealant can move around as the pressure inside and out of the pump change. Also, keep in mind that any disturbance in the flow of water could be a possible source of the problem. So try to lay down the sealant in a way that causes the smoothest flow of water into the pump.

Anyway, hopefully you’ve already been out on the water and had no issues.

 

[2kwik4u]

@itsdgm I agree. I think that's like a big part of @Dami860 issue. I hadn't noticed that in the first posting. Looks like they have it sealed up though. Red circle from their most recent post.

I did add two black circles. Lower center looks like a little bit of damage on the leading edge of that blade. Might be worth a quick touch with the file. middle left circle looks like there might be a ding/dent on that blade? Could be poor lighting as well. Worth a check though.

 

[FSH 210 Sport]

the sleeve seems ok to me. Oddly there are fingernail catching grooves in the crankshaft. I took some pics where that sits.

Those are from where the seals ride.

 

[Dami860]

Those are from where the seals ride.

Ok, so just to confirm, that would be considered normal wear? Thx

 

[FSH 210 Sport]

Ok, so just to confirm, that would be considered normal wear? Thx

Yes… just be sure you put some marine grease in the grooves and on each side when you put the pumps back in to help the seals slide over the grooves.. I usually put a thin coat of grease on the shaft from the base of the splines to after where the seals ride on the shaft.

 

[Dami860]

I followed all the recommendations here and yet the cavitation remains the same. I have a couple videos to share. 1st one shows a couple WOT runs and then one with just easing on the throttle. 2nd video is WOT throttle. Not sure if the motor should be vibrating like that. 2 new items by Sal Damiata

 

[steveinmd]

That cavitation is severe. I fought it with my 195 for a few seasons before I sealed the tunnel and used toilet bowl wax on my clean out plug. One them fixed it, finally. Now I can give lots of throttle from low speeds and it pulls hard.

You have a gargantuan amount of air getting into the pump.

 

[Dami860]

That cavitation is severe. I fought it with my 195 for a few seasons before I sealed the tunnel and used toilet bowl wax on my clean out plug. One them fixed it, finally. Now I can give lots of throttle from low speeds and it pulls hard.

You have a gargantuan amount of air getting into the pump.

Ugh, I hope the toilet bowl wax is the fix. With this being a 2024, I can't believe a clean out plug could have issues already. Thanks!

 

[Steve73]

That cavitation is severe. I fought it with my 195 for a few seasons before I sealed the tunnel and used toilet bowl wax on my clean out plug. One them fixed it, finally. Now I can give lots of throttle from low speeds and it pulls hard.

You have a gargantuan amount of air getting into the pump.

Steve - How did you use toilet bowl wax on the clean out plug? Do you have any pictures of what you did? I have cavitation and I have a lot of water that gets past my clean out plug. Wondering if this would fix both problems.

 

[steveinmd]

Steve - How did you use toilet bowl wax on the clean out plug? Do you have any pictures of what you did? I have cavitation and I have a lot of water that gets past my clean out plug. Wondering if this would fix both problems.

Real simple. The wax comes in a plastic tub and that ish is nasty. Super goey and sticky. I bought mine at lowes but home depot carries it as well. Just smear it on the plug seal. I left it thick to take up any potential gaps. I don't have a water problem on the top side of the plug anymore. It's dry.