Changing Yamaha Jet Boat Pump (Duct Housing) Bearings and Switching to Oil Bath Lubrication

[KXCam22]

Excellent write up!! To remove the grease from the rear bearing (without disassembly - in prep for oil) I wrapped the whole thing in a plastic bag (with my hand inside) and hit it with compressed air. Yuk. Cam.

 

[Bruce]

I wrapped the whole thing in a plastic bag (with my hand inside) and hit it with compressed air. Yuk. Cam.

We need a gross rating!!!!!

 

[RRamsdell]

Thanks for all the details. My starboard pump was making all kinds of noise when I first took it out this year and I thought I had a warped impeller housing, but when I pulled it apart to replace it, rusty water ran out of the duct housing and when I pulled the cone the bearings were rusted and broken.

Your write up and the post on Green Hulk made replacement possible for me to do myself. Total damage was right about $100 in parts, plus some PVC pipe and couplings, a 27mm wrench for the impeller, the shaft holder, and a 1.5" socket to press the reassembled shaft back into the housing.

Thank you!

 

[KXCam22]

Keep in mind that if you use grease, to use the AP#0 or a grease/oil mixture. The AP#0 is a thin grease that flows around a lot more than normal grease. I think so it can reach that rear bearing. Normal grease is thick and may not flow enough to get back there. Adding some gear oil to make a slurry (that flows) is quite common. Cam.

 

[swatski]

Is this a FAQ item? If it is, maybe we can insert the link here?

This is a thread that EVERY current YJB owner will need to read at some point .
Some sooner then others, and it may be referred to a dealer, but either way I don't see a way around that service.

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[RRamsdell]

I greased the front bearing that I may never see again, and then filled the duct housing with lube oil, then dabbed some grease on that rear bearing and filled the cone 1/3 full with grease. I plan on pulling the pumps every 2-3 years and changing out the lube oil to determine if anything further needs to be done.

 

[MrMoose]

@Bruce, do you have a pic of the bearing/cone that did not have water drip out of it? I'm curious to see the difference in the appearance of the grease.
Thanks

 

[Bruce]

@Bruce, do you have a pic of the bearing/cone that did not have water drip out of it? I'm curious to see the difference in the appearance of the grease.
Thanks

This is what it looked like in 2014 before water incursion.



And in 2016

 

[Marvin willis]

That's what mine looked like too

 

[MrMoose]

So, @Bruce and @Marvin willis, the OEM grease looks milky-yellow regardless of whether there is water contamination? The only way to tell that there's water in there is to actually see it drip out? Or, is there any indicator from the appearance of the grease that would tell that there's water?

 

[Bruce]

So, @Bruce and @Marvin willis, the OEM grease looks milky-yellow regardless of whether there is water contamination? The only way to tell that there's water in there is to actually see it drip out? Or, is there any indicator from the appearance of the grease that would tell that there's water?

Had I not seen water drip out I would have put mine back together and oblivious to any issue. The bearings still appeared to be in good shape. Very little water was in there. I imagine they would have been fine for some time but I would not want the expensive surprise others have had when they failed. I suspect the water pushed past the front seal during the rough crossing in 2015.

 

[MrMoose]

@Bruce, it might be an optical illusion, but your 2014 pic looks like there's a drop of water just right of center.

 

[Marvin willis]

I didn't see any water but was told it was the water that made the grease turn yellow. I changed mine after the season was over just to be safe. And changed both jet pumps to the ones with plastic liners bc mine were starting to rub the impeller.

 

[swatski]

@MrMoose The OEM grease that I purchased new and the grease inside the 2016 pump looked identical - I would not call it milky, more like translucent, and opaque, but NOT a milky emulsion. If you have the OEM grease, which I'm assuming you do - that's what you should see inside the pump. Anything milky/emulsified would indicate water intrusion. It looses translucency more than anything else. Think of mustard (NOT necessarily Poupon, just the lowly yellow mustard that is an emulsion holding a lot of water).
Let me know if you want the OEM grease, I have about 2/3 of the bottle left - happy to put it in the mail, just pm me your address.

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[Bruce]

@MrMoose, the factory grease is pretty moist. Nothing ran out at the time.

@Marvin willis, I understand that the grease in our boats was yellow from the factory.

 

[blacksapphirez]

I'm fixin to do this soon... i have some gear oil left and a marine grease for intermediate shaft bearing(one in the engine compartment) if I mix them do you think it will be okay? and would you prefer more gear oil or more grease?

 

[MrMoose]

@MrMoose The OEM grease that I purchased new and the grease inside the 2016 pump looked identical - I would not call it milky, more like translucent, and opaque, but NOT a milky emulsion. If you have the OEM grease, which I'm assuming you do - that's what you should see inside the pump. Anything milky/emulsified would indicate water intrusion. It looses translucency more than anything else.
Let me know if you want the OEM grease, I have about 2/3 of the bottle left - happy to put it in the mail, just pm me your address.

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Thanks @swatski . Yellow-beige?

 

[MrMoose]

@swatski, what do you think about Bruce's 2014 pic of the grease in his cone?

 

[blacksapphirez]

@swatski post again where you found the OEM Grease... please

should be stickied!

 

[Bruce]

@swatski, @MrMoose, @blacksapphirez, do you guys see any need to add additional grease to what the factory included? You can not change the grease without removing or replacing the bearings and seals.

I would have a look, smudge a little grease on the o ring and put it back together unless you see a problem.