Bad Pump Liner? 2012 SX210

[SunkCost]

Hey everyone - first time to post here. I purchased this boat about 6 months ago with 78 hours. It now has 110 hours. At the 90 hour mark I started hearing some grinding noise from the starboard engine/pump. From everything I’ve read on this super helpful forum it is likely a bad pump liner but wanted to get y’all’s opinion before tearing it apart.
- i did not see any obvious wear marks when inspecting with a flashlight
- only used in freshwater
- RPM will fall 100-200 rpm when I hear the grinding noise (assuming it’s binding up)
- Sound stops after about 15 minutes of running the engine (assuming the high spot is being ground down?)

Any input would be appreciated!

 

[tdonoughue]

Hello and welcome to the party!

I don't think you are having a bad pump liner. First, the hours, age and (if your boat really was) only in freshwater would make it unlikely (not impossible). Second, if you hear the sound and then it stops, that does not sound like it. When the liner is bad, it is corrosion expanding the liner. When it contacts the impeller, it gets worse and worse until it stops the engine. I don't think anyone has reported it going 'back' after 15 minutes.

I would pull the pumps and have a good look at what you have going on. I suspect you have something stuck in your impeller or something. At any rate, pulling the pumps gets you two things: 1) you get to clear out anything in there and be certain you got it all and b) you get a good look at the impellers and the rings (so you can see if there really are scrapes in there. While you are there, you can also wiggle things to see if your bearings are shot.

I didn't pull my pumps for the longest time because it seemed like such a big task. It is not. We have several writeups here (including in the FAQ, I think). It is very easy. Do it.

 

[SunkCost]

Thanks for your reply and for the welcome! I will plan to pull it apart and inspect. I was thinking that if the swelling is minor the impeller would grind it down after that first 15 minutes or so of running. I have noticed the grinding is worse the longer it sits - 1 week vs 1 month between uses. I have attached a link with a video. Hopefully it will work.

20200807_233942000_iOS.MOV

MOV File

1drv.ms

 

[tdonoughue]

Worked fine! Yes, that does sound awful. I could be wrong on that, of course. Note that the impeller does not just grind down the ring. The ring grinds down the impeller. On bad cases of ring corrosion there is a huge burr on the outside edge of the impeller from the rubbing. Just have not heard of it getting better after 15 min...

But, pulling the pumps should settle the question pretty conclusively. Either you will have some nice evidence of wearing or not. Then we can go from there.

 

[Seadeals]

It almost sounds like the engine is running rough; but I guess that is just the way it translates on video? I also wonder if it might be a cone bearing that has failed. It could rattle and when not spinning correctly, bump the impeller into the liner. The key will be if you see any unusual wear/damage on the pump liner/impeller. Have you ever lubricated the intermediate housing?

 

[tdonoughue]

Yes, it could be a bearing as well. That is why you pull the pump. Once that is out, if the shaft shakes laterally, you have bad bearings. If you look up where the shaft came from and there is grease and grease on the shaft, your seals are blown in the intermediate. If you have wear on the impeller circumference, you have ring corrosion. If there is junk in your pump... you have junk in your pump. Very hard to diagnose any of that with the pump still on.

 

[SunkCost]

Got it apart and it all looks to be in good shape. I did notice the end of the shaft where the splines are is wet. Maybe water got into the intermediate bearing? Could the bearings/grease be getting warm after 10-15 minutes of use causing the noise to stop?

 

[mrcleanr6]

hmmm hard to say about the water on the splines. that doesnt necessarily mean anything. that could be and probably just from a little water sitting up there in the white thru hull where the shaft goes in. the water is beaded and looks fresh. the grease doesnt look milky either like water has been getting in slinging around for awile. i wouldnt worry about it.

 

[Seadeals]

Would you want to run the engine briefly with the pump out to see if the noise was the intermediate bearing? The pics appear to show everything in operable condition though you can’t see the forward bearing on the pump. Does it turn smoothly by hand? No rattles or play?

 

[tdonoughue]

I agree. Everything there looks very clean to me...

 

[SunkCost]

Would you want to run the engine briefly with the pump out to see if the noise was the intermediate bearing? The pics appear to show everything in operable condition though you can’t see the forward bearing on the pump. Does it turn smoothly by hand? No rattles or play?

Correct - no rattle or play. I did consider running the engine when i had it all part but was unsure if that would negitavely affect anything.

 

[SunkCost]

Here’s some embarrassing, but good news - a fresh set of spark plugs solved the issue. Thank y’all for the suggestions.

 

[Seadeals]

Great news! No need for embarrassment when you fixed the problem.

 

[tdonoughue]

Especially when you share the news like this, so someone else with a similar problem may be able to fix it faster in the future. We call that a win.