Impeller issues - trashed bearing - pump rebuild & impeller swap

[Bruce]

This is my bearing change thread. It was an easy process. Getting the impellers off was the only hard part.

https://jetboaters.net/threads/changing-yamaha-jet-boat-pump-duct-housing-bearings-and-switching-to-oil-bath-lubrication.10155/

 

[Scottie]

How did the boat run before the current issue? Was your RPM at WOT similar on both sides with the OEM impellers?
If it was similar it may be similar to the new hulls where they stock both pumps with the same pitch impelelrs and the differences are very small, negligible for most people, and may not need/benefit from different pitch much.

I was within 200 rpms difference at WOT, but that was mainly due to the L13 cones, and running 3 spacers on the port side, vs none on starboard. There was a pretty big difference before I installed the cones.

 

[buckbuck]

@Scottie Not sure if you realize it but some of us have changed from grease to a slurry of grease and gear oil. Not sure it would have saved your bearing but you might want to consider it on the rebuild.

 

[Scottie]

@buckbuck I have been reading about that. I've read every impeller thread on the forum in the last 23 hours I believe. Ha. I haven't decided on the gear oil yet. I do think it's a good idea, but I would want to tap the cone, and I'm not sure I want to do that with the L13s. I'll keep thinking on it. Had some good success this morning with impeller removal. Starboard side slid right out, nothing more than a pull. Port side (damaged bearing) needed a BFH, but it too came out without much fuss. I put a long impact rated extension through the intake grate and onto the impeller nut, couple a big boy whacks and she was out. So now to choose and order parts. I saw where @Bruce ordered a pump kit that had bearings and seals in it. Have those parts changed over the years? Should I order the kit or piece the parts together from the parts catalog?

 

[swatski]

@buckbuck I have been reading about that. I've read every impeller thread on the forum in the last 23 hours I believe. Ha. I haven't decided on the gear oil yet. I do think it's a good idea, but I would want to tap the cone, and I'm not sure I want to do that with the L13s. I'll keep thinking on it. Had some good success this morning with impeller removal. Starboard side slid right out, nothing more than a pull. Port side (damaged bearing) needed a BFH, but it too came out without much fuss. I put a long impact rated extension through the intake grate and onto the impeller nut, couple a big boy whacks and she was out. So now to choose and order parts. I saw where @Bruce ordered a pump kit that had bearings and seals in it. Have those parts changed over the years? Should I order the kit or piece the parts together from the parts catalog?
View attachment 99006

You still haven’t pulled the impellers off, right?
Hopefully it will go easy.
There were cases were a shaft could not be saved, worst case but I would start there.

Given your side to side difference, I must rescind my opinion, lol, I would try different pitches to even this out before L13 action. IMHO.

—

 

[Bruce]

@Scottie, there have been changes in the impeller shaft over time. I would start with the Yamaha bearing part numbers for your boat and look for kits from that point.

 

[Scottie]

All parts have been ordered. Going with 6CW impellers and delrin wear rings. Impellers arrived today.

 

[swatski]

All parts have been ordered. Going with 6CW impellers and delrin wear rings. Impellers arrived today.
View attachment 99396

This should be great!
Please keep us posted!!!

—

 

[Scottie]

No trouble at all with the impeller removal. Used the swatski wrench w/ a 6ft cheater, and a vice. I'll know more tomorrow, but it looks like MAYBE the water didn't come in through the cone. In the pics below you can see the starboard side (sound, no damage) with the washer pushed up against the housing, like it should be. The port side (trashed) has a large gap in that same area. I should be able to see when I remove the housing, but I don't see how water wasn't getting in there.

 

[Beachbummer]

I'm not sure exactly what the washer does, but the water is kep outside by a seal that is under the washer, not by the washer itself. Water can ever via the seal or the cone matting surface/oring (I guess also through the case if the case was cracked or damaged, but nobody has ever reported that, that I remember).

I think you are very confident in how water got in

Best of luck with the rebuild.

 

[Scottie]

Here's a shot comparing the impellers. 6CW01 on the left and 6AP10 (stock 212x, at least for 2013) on the right.

 

[swatski]

Here's a shot comparing the impellers. 6CW01 on the left and 6AP10 (stock 212x, at least for 2013) on the right.
View attachment 99713

Wow. Can not wait for you to try those on!
(I love looking at impellers, this is a great pic)

--

 

[Scottie]

Yesterday I got the shafts pressed out of the housings, and all bearings (and bearing remnants) removed from the housings. I found some pretty serious carnage unfortunately. The exploding bearing wreaked havoc on the inside of the housing. Deep gouges everywhere. I've decided to replace it, so assembly will have to wait until the new part arrives. Also, the pump kit I ordered from SBT did not have the proper bearings in it, so those are being swapped as well. On the port side, the inside bearing was seized, and it appears to have been that way for quite a while. I am convinced that the bulk of the water intrusion happened there, as there's no way there was a decent seal given the position/condition of the inside seals, and the obvious damage to the inside bearing, which appears to have failed long before the rear. When the rear bearing did fail, there was apparently so much carnage happening inside, that the washer was literally welded to the rear nut, from the inside. Crazy pic below. The nut/washer on the right is what was removed from the starboard shaft, the one without damage.

 

[Scottie]

More progress tonight. I pressed bearings and spacer on both shafts. One shaft is brand new, the other was undamaged so it's being reused. Here's some pics and a video of the process. I'm using a $150, 20 ton bearing press from harbor freight. I am CERTAIN there are easier, smoother presses available, but this one certainly does the job, if not a little unwieldy.

IMG-20190723-WA0027.jpg

• Scottie
• Jul 23, 2019

Inner bearing prior to installation

IMG-20190723-WA0025.jpg

• Scottie
• Jul 23, 2019

Press setup with 1 1/8" pipe as a die

20190723_174640.jpg

• Scottie
• Jul 23, 2019

Inner bearing installed

20190723_194534.jpg

• Scottie
• Jul 23, 2019

Yamaha service manual specs .910" between inner bearing and shaft "collar"

IMG-20190723-WA0034.jpg

• Scottie
• Jul 23, 2019

Completed impeller shaft

 

[buckbuck]

Please keep those pictures coming. We are all going to be where you are someday.

 

[Brad_Ct]

Great write up, be careful you don’t drop anything on your toes

 

[Scottie]

New pumps are finished! Planning to reinstall tomorrow afternoon and get the boat back in the water! I'm really happy with how this has turned out so far. I honestly can't imagine anyone else paying attention to the details like I have. I'm sure someone else would've done it faster, but I don't think better, and I like knowing what I've got. Hopefully I'll still be happy tomorrow! I'm planning to come back to this thread and clean it up, with a parts list, tool list, and step by step on the bearings press. For now, here's more pics.

20190724_164058.jpg

• Scottie
• Jul 25, 2019

Orientation of oil seals, prior to installation.

20190724_164128.jpg

• Scottie
• Jul 25, 2019

Socket used for oil seal installation.

20190724_165525.jpg

• Scottie
• Jul 25, 2019

Oil seals installed into pump housing

20190725_175341.jpg

• Scottie
• Jul 25, 2019

Depth of bearing tunnel in housing, 3.542"

20190725_175601.jpg

• Scottie
• Jul 25, 2019

Width of impeller bearing assembly, 3.142"

20190724_171320.jpg

• Scottie
• Jul 25, 2019

Prior to final press.

20190724_171715.jpg

• Scottie
• Jul 25, 2019

Pressing shaft with bearings into housing.

20190725_180737.jpg

• Scottie
• Jul 25, 2019

Shaft with bearings pressed into housing. .400" relief

20190725_192225.jpg

• Scottie
• Jul 25, 2019

Finished pump housing.

20190725_192904.jpg

• Scottie
• Jul 25, 2019

6CW Impeller installed.

20190725_201059.jpg

• Scottie
• Jul 25, 2019

Impeller assembly - finished.

20190725_201105.jpg

• Scottie
• Jul 25, 2019

Impeller assembly - finished.

 

[Beachbummer]

Does the shaft come out opposite of how you pressed it? (By pushing the exposed long shaft towards the pump?)

And, what's the role of the nut? Does it keep the shaft from pursuing it's way out during boat operation? Or is there another purpose?

Looks awesome!!!!

 

[Scottie]

For removal, the pump would be oriented just like the pics above, but you would use a die slightly thinner than the shaft, and the shaft would be pressed down, through both bearings and out of the housing through the bottom. This would leave the bearings and the spacer in their spot inside the housing. Then, flip the housing over, pry out the 2 oil seals, and using a die the same size as the inner race for the inner bearing (now on top), press through the housing. The rear bearing will come out the bottom first, then the spacer, then the inner bearing. Does that make sense?

The rear nut and washer is just a mechanical hold, to prevent bearing travel, I believe.

 

[Beachbummer]

Ok, thanks. I wondered how to remove. I failed last year and the bearings were in pretty good shape. Your pictures and explanation are awesome!!! Thanks so much!