At 4500 rpm’s it feels like a clutch is being pressed

[2Point-Oh!]

That is the best way to explain it!
2010 SX210
I have thrust to move around the marina and the no wake zone. But once I throttle up and get to around 4500 rpm’s the motor will rev up to 8k rpm’s and the boat goes nowhere. It’s just like a clutch is being pressed.
I have removed the jet and the shaft and see no damage. Wear rings are after market but in good shape. The clean out plugs are in great shape as well.
I have been in shallow water with lots of seaweed lately. I have tested in a non seaweed area and made sure everything was clean. Still having same issues.
Now both motors are doing it. I no longer think it is anything to do with impeller or shaft.
Anyone have and experience with this one?

 

[Acard7]

Take some pictures of the new wear rings with the impellers, you’ll have to do this from the bottom of the boat via intake grate.. Just wondering if the clearance on them is off. I assume when you’re on the water and it happens you immediately check the clean out ports? Sounds like cavitation for sure. Haven’t had this issue before? Were you the one to replace the wear rings or did you buy it that way?

 

[2Point-Oh!]

Take some pictures of the new wear rings with the impellers, you’ll have to do this from the bottom of the boat via intake grate.. Just wondering if the clearance on them is off. I assume when you’re on the water and it happens you immediately check the clean out ports? Sounds like cavitation for sure. Haven’t had this issue before? Were you the one to replace the wear rings or did you buy it that way?

 

[2Point-Oh!]

Yes I replaced the wear rings. But that was a few years ago and have put many hours on them with no problems

 

[Acard7]

Next thought is your bearings on the impeller shaft and intermediate bearing behind the engine. You can check the intermediate bearings while underway to see if they leak water. The impeller bearing on the shaft I’m not sure how to know when it’s bad, there’s threads on here of people changing them though. Have you put new grease in the cones? That’s where you can get a peak at one.

 

[2Point-Oh!]

I did not check the cones when I had everything apart. I will check them though. I was wandering about the intermediate bearings. I find it odd that both are acting this way. I should be able to work on it today. Thank you for your input!

 

[Acard7]

Ya I’m still not convinced those are the issues either…Feel it has to do with cavitation but it’s a start for you!

 

[David Martin]

Cavitation can be a real pain to solve sometimes on an older boat...............props need to have nice clean smooth edged......look for dings ect.........Liners to props need to be check with a feeler gauge service manual has specks on mine is .014 to .018 this gap needs to be check all around the liners. The run out limit of the shaft/unit has a max spec in the service manual. Now if she passes all the measurement and impeller blades are clean........the service manual shows around 10 areas to be caulk smooth in the tunnel area and a few more on the gates as well.

 

[Beachbummer]

It's usually some sealant/caulking that has left it's original place. Don't just check visually, also grab/pull around. if it's loose, it gets sucked into the water path and makes a mess. I have stopped using caulk/sealant and instead use WaterWeld to fill in gaps in the "permanent" parts of the transom plate and intake tunnel. Just last month I had some new gaps, I saved the outing by throttling up gently and giving power with the other engine until it did not slip. Visual inspection revealed several gaps between the plate and the boat towards the bottom, and around that transom plate in the back. (I ended up removing the pump to do it correctly. I almost got it via the clean out on first try that first week, but with no visibility I left some glops that needed clean up, and some gaps I could not find by touch alone. Sometimes the laziness pays, but I had to do the job twice here, I almost got away with it).

Use whatever sealant you like, but so far I have not had to replace any WaterWeld I have added, this is the second or third time some silicone falls off and causes some cavitation, but this was the worst impact, as the piece that fell off was pretty big. Be sure all the gaps are filled and hopefully you will be back in good shape.

I removed only the pump and filled all gaps in the areas shown in the diagrams to the right, and also right behind the plate where the pump bolts into.

 

[2Point-Oh!]

It's usually some sealant/caulking that has left it's original place. Don't just check visually, also grab/pull around. if it's loose, it gets sucked into the water path and makes a mess. I have stopped using caulk/sealant and instead use WaterWeld to fill in gaps in the "permanent" parts of the transom plate and intake tunnel. Just last month I had some new gaps, I saved the outing by throttling up gently and giving power with the other engine until it did not slip. Visual inspection revealed several gaps between the plate and the boat towards the bottom, and around that transom plate in the back. (I ended up removing the pump to do it correctly. I almost got it via the clean out on first try that first week, but with no visibility I left some glops that needed clean up, and some gaps I could not find by touch alone. Sometimes the laziness pays, but I had to do the job twice here, I almost got away with it).

Use whatever sealant you like, but so far I have not had to replace any WaterWeld I have added, this is the second or third time some silicone falls off and causes some cavitation, but this was the worst impact, as the piece that fell off was pretty big. Be sure all the gaps are filled and hopefully you will be back in good shape.

I removed only the pump and filled all gaps in the areas shown in the diagrams to the right, and also right behind the plate where the pump bolts into.

Thank You! I This is something I did not pay attention too.