YAIT (Yet Another Impeller Thread)

[tdonoughue]

So, the boat is now at just over 100 hours. Last two times out, it seemed a little sluggish. Mind you, I did have more people on board than usual, but even when I was down to 2 people and 1/2 a tank of gas, it took me the span of the lake to get it up to 47 mph, WOT, 7500-8k rpm on each engine, creeping up from about 43 mph.

This evening, I did the obvious thing (I think): I pulled the pumps for the first time. Clearance looked fine, but when I pulled them...

That was the starboard side. Port side had a nick or two, but nothing like the starboard side here. So, clearly that is bad and could be causing cavitation. Took them home (actually both sides, while I was at it) and cleaned them up with a file:

Much better. May need to replace them shortly, but this is at least worth a try (especially because the boat has a date on Saturday).

As a sidebar, while I had them here at home (and having been properly tutored by this site), I pulled the cones. As messed up as the starboard impeller was, inside the cone was pristine--picture perfect. Port side gave me this:

So, this is water intrusion. And then we get to my questions:
1) As to the cone I already pulled out the bad grease, cleaned up the gasket and will get new grease and reassemble. Does the gasket need to be replaced? Obviously I don't have one (and won't by Saturday), so if the consensus is yes, I will pull it again next week and replace that and the grease again.
2) When I pulled the pumps, here is what I had for the inside (starboard):

Port side was substantially the same--same type of wear on the ring. Same white stuff right behind the ring sporadically. Silicone in place everywhere, but not smooth (you can see it best on the left in this picture). I am pretty sure this is how it came stock. Problem? Anything else I am missing from this picture? That said, I do know there is some silicone missing from the forward end of the grate that I can replace. But that has been gone for a while without symptoms.
3) Your guess: will I need at least a new starboard impeller very, very soon? Should I replace in pairs?

Thanks in advance for all opinions. Especially those of our resident impeller-master, @swatski .

 

[swatski]

So, the boat is now at just over 100 hours. Last two times out, it seemed a little sluggish. Mind you, I did have more people on board than usual, but even when I was down to 2 people and 1/2 a tank of gas, it took me the span of the lake to get it up to 47 mph, WOT, 7500-8k rpm on each engine, creeping up from about 43 mph.

This evening, I did the obvious thing (I think): I pulled the pumps for the first time. Clearance looked fine, but when I pulled them...
View attachment 79308
That was the starboard side. Port side had a nick or two, but nothing like the starboard side here. So, clearly that is bad and could be causing cavitation. Took them home (actually both sides, while I was at it) and cleaned them up with a file:
View attachment 79309
Much better. May need to replace them shortly, but this is at least worth a try (especially because the boat has a date on Saturday).

As a sidebar, while I had them here at home (and having been properly tutored by this site), I pulled the cones. As messed up as the starboard impeller was, inside the cone was pristine--picture perfect. Port side gave me this:
View attachment 79314
So, this is water intrusion. And then we get to my questions:
1) As to the cone I already pulled out the bad grease, cleaned up the gasket and will get new grease and reassemble. Does the gasket need to be replaced? Obviously I don't have one (and won't by Saturday), so if the consensus is yes, I will pull it again next week and replace that and the grease again.
2) When I pulled the pumps, here is what I had for the inside (starboard):
View attachment 79315
Port side was substantially the same--same type of wear on the ring. Same white stuff right behind the ring sporadically. Silicone in place everywhere, but not smooth (you can see it best on the left in this picture). I am pretty sure this is how it came stock. Problem? Anything else I am missing from this picture? That said, I do know there is some silicone missing from the forward end of the grate that I can replace. But that has been gone for a while without symptoms.
3) Your guess: will I need at least a new starboard impeller very, very soon? Should I replace in pairs?

Thanks in advance for all opinions. Especially those of our resident impeller-master, @swatski .

Looks like you cleaned that impeller real nice! But it may or may not work, no way to tell but in the water. The leading edges seem very sensitive when it comes to performance.
The tunnel/sealant between the pump segments looks like it needs to be replaced/resealed. I would go with 5200 (3M) - at the least, silicone will not last. May want to use some silicone (gasket maker, blue RV type) between the segments, but not where the white stuff is.
Your wear ring seems fine. I bet the impeller leading edge is/was the reason for cavitation, and it would make sense - slow acceleration but same top end, more of less.

The water intrusion issue is something to keep an eye on! Sounds like you caught it right in time, before a disaster! Replacing the o-ring and the grease - certainly good idea.

Keep us posted.

--

 

[MrMoose]

@tdonoughue , thanks for sharing your latest experience. With regards to your bearing, did you actually see water in it when you removed the cone? Any chance you could share a pic of the one that does not have suspected water intrusion, for comparison? Regarding the o-ring seal for the cone, Yamaha says that it should be replaced when the cone is removed and reassembled, which is supposed to be annually. … but I get the sense that this is not common practice among owners and dealerships.

 

[tdonoughue]

Wish I had taken one of the non-intruded one, now. Unfortunately, I did not (and figured, finding the first one fine, likely the second one was fine, too--nothing to report). The grease was a nice golden color, mostly clear. So I reassembled (yes, reusing the same gasket). But then I pulled the second...

Yes, on this one pictured I could actually see water (a few drops) on the bearing side (not in the cone so much). You can see it a bit on the picture along the bearing race at the bottom. Also note how the grease particularly in that area is gloppy rather than smooth--that is the water (actually, the grease sitting on the water).

Thanks for the info on the gasket. That is about what I figured (after all, the water got in there somehow...). So I will order up two and replace them in the next week or two. Upside: I will be able to post a pic of a non-invaded one then. Hopefully.

 

[MrMoose]

Wish I had taken one of the non-intruded one, now. Unfortunately, I did not (and figured, finding the first one fine, likely the second one was fine, too--nothing to report). The grease was a nice golden color, mostly clear. So I reassembled (yes, reusing the same gasket). But then I pulled the second...

Yes, on this one pictured I could actually see water (a few drops) on the bearing side (not in the cone so much). You can see it a bit on the picture along the bearing race at the bottom. Also note how the grease particularly in that area is gloppy rather than smooth--that is the water (actually, the grease sitting on the water).

Thanks for the info on the gasket. That is about what I figured (after all, the water got in there somehow...). So I will order up two and replace them in the next week or two. Upside: I will be able to post a pic of a non-invaded one then. Hopefully.

@tdonoughue, @Bruce and others have disassembled and replaced bearings and as such there's lots of knowledge to tap into.
Do not assume that the water intrusion is via the o-ring on the cone. I get the sense that it is more likely that the water is coming in from the front, not the cone. I hope that others with more experience will chime in.
Good luck.

 

[tdonoughue]

Coda: Got some grease, repacked the bearings--no problems.

Took pumps to the boat and put them on with the 4 big bolts a piece--no problems.

Attached the reverse gate to the bucket--snapped the end of the port side reverse gate cable off. Figured out that the reverse gate attaches to the cable with a spring-loaded connector. Videos showed that you should detach the bolts on the side. You can do that, but when you are unscrewing and reattaching, you need to hold the bracket with a pliers or something or you will pull against the cable and -- snap! In the future, I would use the spring loaded thing to disconnect.

Supposed to go out Saturday, so I found the die of the right size, so I am hoping I can revive enough thread to reattach the gate at least temporarily. Next thread will apparently be replacing a reverse gate cable... <sigh>

 

[tdonoughue]

Sorry there were no pics. Was too depressed last night.

This morning's plan: use a steel cable to clamp it together. Should work for a day.

 

[boudin]

@tdonoughue if you find you need to rebuild pump(s), bring them to me and I'll help. I have all the tools including a shop press. I'm about an hour from you.

The filing you did on the impeller will help, but keep in mind you are increasing the clearance and it will likely cause cavitation. OEM impellers are pretty cheap on partzilla.com... $194. With no tax and free shipping, it's a good option to having yours rebuilt.

It's common to see a tiny bit of water in the cone, and judging from the photo it looks fine. Do the bearings move smoothly? But yes, replacing the o-ring when rebuilding the pump is a good idea. They are cheap.

-Greg

 

[Beachbummer]

I have revived a snapped cable with a die and a coupler before. Don't give up the weekend for this. You can make it work!!

Jb weld, a clamp, and a threaded rod may also help you out.

Best of luck

 

[boudin]

In a pinch, I would just delete one of the reverse gates for the Saturday trip. You'll survive with just one of them.

-Greg

 

[tdonoughue]

Thanks, folks. Yes, I have my tap & die set pulled and a trip to Home Depot scheduled to see what I can fashion (may do the connector, may just put the end on once I die it, may use the cable thingy). But never would have through to take the bucket off! Good idea, too.

@tdonoughue if you find you need to rebuild pump(s), bring them to me and I'll help. I have all the tools including a shop press. I'm about an hour from you.

The filing you did on the impeller will help, but keep in mind you are increasing the clearance and it will likely cause cavitation.

Very nice offer! Thank you very much! Might take you up on that. I did not file any of the side edges, only the leading edge that was messed up. I am mindful of the clearance. So I am optimistic this might help. Also rather planning that soon I will be undertaking to replace them. Actually found them at ~150 on yamahasportsplaza (but shipping may equalize that--didn't check).

 

[tdonoughue]

Oh, and yes, the bearings are fine in the water-intruded one. Only a little bit of water in there, so I am not worried, but did not want to let it that way. Cleaned it out and repacked it. Turns fine. Very smooth. No issues there.

 

[tdonoughue]

A pic of the problem:

The first brilliant solution was to recut the threads and use a connecting nut. I could only find SAE connecting nuts, but I am recutting the threads anyway, so what is the difference, right?

So, got all ready to go and figured out that my tap & die set is metric. Oops.
Plan B:

Nuff said. Even adjusted them so they are all even in the back.

 

[boudin]

Pretty nifty solution!

 

[tdonoughue]

Would have been more nifty had it worked for more than 5 min in the water.

However, I did wind up using half of @boudin 's solution. So, we got past the no wake, stopped to put on sunscreen. When I went to move forward, I could tell things were not right. I reached down there and of course the bucket was free. So, plan B for on the water was to tie the bucket up. So I got a section of line, reached down and lifted the bucket. When I did that, the bracket at the top spun and stuck the bucket in the open position. No line needed.

And so we did the day on the water that way. All was fine (except for that incident near the dock where I instinctively put the starboard in reverse, propelling us forward--recovered in time, but did kiss the dock a bit). Day was had, we all had fun, and there you go.

Next week, when the part comes in, I will learn how to replace a cable.

Oh, and the impellers: a bit better. Probably not as good as new, but better and certainly not worse. Didn't do the 5200 in the pathway yet (would not have had time to cure). That comes next week, too. Hopefully that helps some more.

Thanks to all you folk for the support and advice along the way.

 

[tdonoughue]

Another coda:

The new cable came in this week. Replaced it and all is well (I will write that up on another thread so folks can find it). Yes, I have some pics, so it did happen.

While I was there playing with the silicone, I also smoothed out the outer/bottom of the intake (we were tired, I didn't re-pull the pumps to do that part yet).

I claim win.

 

[swatski]

(I will write that up on another thread so folks can find it). Yes, I have some pics, so it did happen.

Please do!

I see this install in my future... Probably another couple of years, but I like to be prepared, lol.

--

 

[MrMoose]

@tdonoughue, in one of your earlier posts, you suggested that the breakage was your fault. Sometimes things just break... cuz they just break. Chances are, it would have broken SOONER than later, regardless of your actions.
This past week, I simply removed the negative battery terminal connections to pull my pump (I doubt anybody does this, but the service manual says to do so) and one of the small wires broke off at the connector. Happy that it happened in my driveway... just like you should be happy that your cable broke when the boat was on your trailer.
There's always a bright side.
Keep sharin'

 

[tdonoughue]

What you say is true, friend @MrMoose . However, in this instance it was really me. I didn't hold the cable or the end attachment before I tightened the bolt. But for that, cable probably would have been good another 4 years.

But, you know, you fix things and save yourself a lot of money. Then sometimes it costs you a little more and you learn a few more things than you anticipated. All part of the fun and learning. And of course sharing.

 

[Beachbummer]

But with good labor being so expensive and rare, even if you brake something 9/10 you still come out way way ahead.