Yamaha AR-190 cavitation issues

[Riley Hunter]

I’m having cavitation issues under load at slow speeds. Only thing I see is maybe a little bend in the impeller and on the ware ring you can see lake grime in spots but not in other spots like the impeller is out of round or the ring is out of round. I have no noticeable noise. what’s your thoughts

 

[2kwik4u]

That bend isn't great, but shouldn't be cause for alarm.

How does the sealant between the intake tunnel fiberglass and the jet pump casting look? Small pieces of silicone and gaps in sealant can lead to cavitation pretty quickly. Sealing the intake tunnel was the biggest benefit for me. The L13 cone helped some, but not nearly as much as sealing up that tunnel.

I would take something and bend that blade out as best you can. Then take a file to the edges and deburr them. Don't remove a ton of material, just remove and absurdly sharp points. Finally, reseal that intake tunnel. Try those and see where you get.

Once you have the pump back together, check the clearance between the blades and the wear ring. I think the spec is 0.030in, but I would have to double check. I think it's in the service manual.

 

[2kwik4u]

Red circles look like there is some silicone poking out in the flow. Remove/Trim that back. Blue circle looks like it's missing sealant.



Here's where I resealed my intake tunnel. Made a noticeable difference. https://jetboaters.net/threads/hero-or-zero-resealed-my-jet-pump.17845/

 

[Riley Hunter]

Red circles look like there is some silicone poking out in the flow. Remove/Trim that back. Blue circle looks like it's missing sealant.

View attachment 159682

Here's where I resealed my intake tunnel. Made a noticeable difference. https://jetboaters.net/threads/hero-or-zero-resealed-my-jet-pump.17845/

Well I removed as much caulk as I could. I’m going to use 3m 5200 I went ahead and ordered a new impeller and housing just to be safe.

 

[2kwik4u]

Well I removed as much caulk as I could. I’m going to use 3m 5200 I went ahead and ordered a new impeller and housing just to be safe.

OOf......That right side in the first picture looks like you're missing quite a bit of sealant in there. Between the reseal and the new parts I would expect you'll be in good shape.

I boat in fresh water inland lakes, and have VERY little abrasion from the water, and have had VERY little cavitation problems, so I'm basing my judgement here off what I've seen others go through, and what solved the issues for them. I had SOME cavitation early on, but once I sealed the tunnel and put the L13 on it in 2018, I'm on the tail end of season 4 of quite literally forgetting that it's a problem. I have to work hard to load the boat heavy, try to accelerate, and turn at the same time to get some cavitation. And that's a rarity unless I'm pulling a tube with a bunch of weight/people in the bow.