Performance / Cavitation / Impeller Slippage in Twin Engine Jet Boats - help me understand

[blacksapphirez]

I was thinking putting OEM matching impellers ...but that seems like a lot of work lol

 

[swatski]

Look what has arrived!
A nice pair.



Those are really high quality parts. The base is tapered 3deg, but it is hard to see in the pics.
I am kicking myself for not starting this project earlier, it finally got cold here. I'll have to see what I can do.

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[blacksapphirez]

i'm afraid to ask... is it $298... PER PIECE?!

 

[swatski]

Yes, that's the list price. However, there is a 10% discount on orders through his site, and Jerry was running a black friday special of sorts, so it was about $50 off per piece.
Yes it's a lot of money. If it works, I will be a HAPPY CAMPER. But it could bomb, and I could take it on the chin.

We will see. When I played with the L13 in the 190, there were some idiosyncrasies I could not explain, so at the end of the day it is all purely empirical, try-and-see exercise. For example, it worked amazingly well with the OEM impeller w/certain spacer/venturi nozzle combinations, but it was kind of in a narrow band. And I could not get it to work with a Solas impeller for some reason. So, with the twin... I am just hoping for the best!

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[swatski]

Preparing for the L13 cone install and testing, I had to tackle the old problem, LOL - what grease to use (inside the cone)? Have seen anything from bearing grease to grease-gear oil mixes to oil baths used in those applications.

Not to complicate things, I wanted to stay with the OEM solution. The OEM pump grease is lithium soap based, nothing special there, but it is semi-liquid (so not available in regular grease tubes) and has very distinct specs for high pressure/low temp pump-ability. It is not readily available (and in fact elusive, as many here know). It is not a regular maintenance item. (I think it should be, as water intrusion is only an o-ring away, but that is for a different discussion).

I'm sure there are greases with better specs, but I figured the OEM solution may not be a bad idea given:
1. the shear number of Yamaha pumps in use with no evidence of problems
2. I have yet to hear of a pump bearing failure caused by anything other than water intrusion
3. once you have water intrusion, there is no magic...

So, I (finally) found the OEM pump grease! Well, finding it in 55gal barrels is one thing (easy), retail sizing and available in the US is another. After lots of searching and few phone calls, I am 99.9% positive this is the thing. I have it ordered, have not received it yet.

So, here is what Yamaha puts into the pump bearing cones in Japan (called "EPNOC grease AP #0" or "EP" in the schematic in service manual):
http://www.noe.jx-group.co.jp/english/products/lubricants/e71_enprlu_grease.html#product_0


The US equivalent is "Mobilux™ EP 0":
http://www.mobil.com/english-US/Grease/pds/GLXXMobilux-EP-Series

The source of Mobilux EP 0 (for retail quantities):
https://redidriver.com/my-redi-driver-store/8-oz-ep-0-grease-for-redi-driver-free-shipping-in-usa/

Will see when I get it, hopefully that is the thing!

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[dan144k]

I have always the yamaha grease tube, grease is blue in color.

 

[sstegh]

I think Madona use to wear a pair of those.

 

[swatski]

I have always the yamaha grease tube, grease is blue in color.

Yep, I have done that in the past, too.


However, the OEM pump grease is different.


I don't know how to get it from Yamaha...

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[swatski]

I think Madona use to wear a pair of those.

Correct.

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[blacksapphirez]

maybe local yamaha dealer can give you some?

 

[swatski]

maybe local yamaha dealer can give you some?

I find asking my dealer about aftermarket mods is like asking a lamppost how it feels about dogs...

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[blacksapphirez]

i feel you on that one.... any other dealer that may have marine grease? can't be so specific that only yamaha carries it

 

[swatski]

i feel you on that one.... any other dealer that may have marine grease? can't be so specific that only yamaha carries it

Correct. And I found it! Sorry, it just got buried in the post above, but this is it:
https://redidriver.com/my-redi-driver-store/8-oz-ep-0-grease-for-redi-driver-free-shipping-in-usa/

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[KXCam22]

The jet ski guys use a synthetic amsoil grease/oil mix to create a slurry about the right consistency. The APO#0 grease does not have any special lubricating qualities but is a thinner grease that flows better, and so will flow to get to that pesky back bearing by the seal. I could not get the APO#0 grease so I was going to do the grease/oil slurry but then just ended up using oil. I works well. Cam.

 

[swatski]

Good points @KXCam22! The OEM pump grease is lithium based, nothing special but indeed semi-liquid for high "low temp pump-ability".

I wanted to stay with the OEM grease, primarily for warranty considerations, and had very hard time tracking it down. But finally I found it here:
https://redidriver.com/my-redi-driver-store/8-oz-ep-0-grease-for-redi-driver-free-shipping-in-usa/

And I got it - just arrived today!

The US equivalent, "Mobilux™ EP 0"

It does look and feel like the OEM, and I am excited. Except of course it is like 10deg F outside...

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[blacksapphirez]

now how would you put this in... fill the cone half and quickly slap it on hoping it wouldn't all leak out?

cuz I'm thinking of doing maintenance on the cone grease in the spring time

 

[swatski]

now how would you put this in... fill the cone half and quickly slap it on hoping it wouldn't all leak out?

cuz I'm thinking of doing maintenance on the cone grease in the spring time

I'll take some pics when I get to it and open the cone up. I would think to clean up the cavity/ bearings off, especially if there is any grease that might be hardened or so, and replace with a similar amount of new grease, maybe top it off a bit. The volume in the manual is 0.7oz.

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[KXCam22]

Thats a good find. The smallest i could source at the time was a 5 gal pail. I got the old grease out with compressed air. Put it in a plastic bag first or you will get a surprise.