Pump Cone Oil Bath Mod - Long Term Results

[KXCam22]

It has been 90 hours since I modified my pump cones to use an oil bath instead of the AP#0 grease. I got this idea from the PWC crowd. I had planned to change the oil every couple of seasons, but never got to it. Changed the oil yesterday and after 90 hours the 100 cc of oil looked good. There was definitely a bit of water contamination but the oil absorbed it with no issues. I used 80W90 amzoil GL5 gear lube. I planned to use Mercruiser synthetic leg oil but shop wasn't open on Sunday so I used the same Amsoil I used last time. I measured the oil quantity this time and it took 100cc to fill the cone and bearing space about 3/4 full. I am very happy with how it is performing, though with only 100cc of oil a guy should maybe change once a year. It certainly doesn't take long to pull both pumps and change the oil. As a test, I ran a super magnet through the used oil and got ZERO metal. Pulled one cone to inspect and it was super shiny and clean inside. Cam.

 

[Speedling]

Any benefit other than easier to change and keep up on it?

 

[Gym]

Great info @KXCam22. I remember when you converted your cones. Thanks for the feedback.

 

[swatski]

It has been 90 hours since I modified my pump cones to use an oil bath instead of the AP#0 grease. I got this idea from the PWC crowd. I had planned to change the oil every couple of seasons, but never got to it. Changed the oil yesterday and after 90 hours the 100 cc of oil looked good. There was definitely a bit of water contamination but the oil absorbed it with no issues. I used 80W90 amzoil GL5 gear lube. I planned to use Mercruiser synthetic leg oil but shop wasn't open on Sunday so I used the same Amsoil I used last time. I measured the oil quantity this time and it took 100cc to fill the cone and bearing space about 3/4 full. I am very happy with how it is performing, though with only 100cc of oil a guy should maybe change once a year. It certainly doesn't take long to pull both pumps and change the oil. As a test, I ran a super magnet through the used oil and got ZERO metal. Pulled one cone to inspect and it was super shiny and clean inside. Cam.View attachment 37848

Great info, thank you for sharing.
Now you guys just need to switch to the Lucky 13 cone and you will be all set .

 

[KXCam22]

The Lucky 13. Is that the one with the different/longer taper? Speedling, When you take apart the cone It is obvious to me that an oil bath will give better lubrication. Nothing wrong with the grease - Yamaha knows their stuff. Best analogy is a large truck/trailer axle. Our smaller trailer wheel hubs have grease packed bearings which require maintenance, re-packing etc. Large trucks/trailers use oil bath hubs that last forever, hi mileage with low maintenance. It would be nice to have a touch more oil volume but the results were good. Cam.

 

[Bruce]

Why do you think the water contamination occurred? Did you change the O-ring when you converted to the oil bath? Did you this time?

 

[KXCam22]

The o-rings are perfect and well sealed. I would guess that the mild water contamination is coming through the rubber shaft seal behind the impeller. Like an I/O leg I think there will always be a miniscule ( read teeny) bit of water entry after the boat has racked up some hours. I had planned to use the synthetic mercruiser leg oil since it has more water absorbing additives in the oil, being designed for that type of service. Since the jets are off I took the time to fill in any discontinuities (gaps) between the aluminum jet housing mount plate and the FG boat hull. I had about a 3/8" step on the inside of both which is known to cause cavitation. A couple layers of 3m 4200 filled it nicely. I found that rubbing the wet 3M with laquer thinner smoothed it out, similar to smoothing RTV with water. Cam.

 

[Bruce]

@KXCam22, did you install new bearings when you converted? Did you pack the bearings with grease?

 

[Speedling]

What is the benefit of the Lucky-13?

It smoothes out the transition and fills the orifice some to reduce cavitation and increase pressure.

 

[Bruce]

@KXCam22, I just replaced the bearings in my pumps. I am following you in switching to an oil bath. Do you see a real benefit to having the fill hole in your cones?

I am considering the option of adding the 100cc of oil while the pump is out of the boat and vertical then installing the cone and installing in the boat. Changing the oil will require pulling the pump each time but to get to the fill bolt you have to disassemble the steering, shifting and remove the four bolts anyway so pulling the pump and standing it vertical is a minimal addition.

 

[buckbuck]

Bruce, that is a great idea. Sounds like I am finally going to follow Cams advice.

 

[Bruce]

I found that the housing with bearings installed holds 70 cc while the cone holds 60 cc.

I put 70 cc of Amsoil marine gear oil in each housing, installed the cone and left them sitting vertical to check for leaks.

What do you think about having a slightly over 50% oil bath?

 

[KXCam22]

Bruce,
I think the real advantage of the drain hole and plug, besides being easy to install, it on subsequent oil changes. With the drain hole you don't have to disturb the integrity of the cone o-ring assembly each oil change. It also allows a bit more oil inside. The more oil the better but I there needs to be a tiny bit of air space inside for expansion. I think your method will be fine. Also, the amsoil marine gear lube will be better suited for the service than the regular amsoil that I used. I think the true benefit of this mod is to make it easy to change the oil each season which gives a great excuse to pull off the jets and give them a once over, grease the splines etc. It really does not take much time to take off both jets, maybe 20 minute. I fill mine with the jet held horizontal. Another thing I learned from a loctite training course is that blue loctite is better to use on underwater marine bolts (read jet pump) that the anti-seize that I normally use. The blue loctite seals the threads completely against water (and hence corrosion) penetration. I used blue on mine after cleaning the old anti-seize out of the threaded holes.. I also came to my own conclusion that the pump casing sealant is less about sealing the pressurized pump water inside that keeping water caused corrosion out of the pump casing mating surfaces. My next fix is to tighten up the wiggly jet nozzles - probably not a real issue but it bothers me. I have $2.80 worth of metric brass bushings on the way. Cam.

ps. For those who like way too much info (like me) blue loctite is actually liquid/paste plastic that cures in the absence of air and the presence of metal. It will not cure on plastic.

 

[Bruce]

I just reinstalled the oil bathed pumps and fired her up in the garage. My initial impression is that the pumps are much quieter!

 

[KXCam22]

Excellent. Mine seemed a bit quieter too. It was noise that made me inspect them in the first place thinking I had a rusted bearing. Cam.

 

[Bruce]

I found water in one of my cones. The bearings were still in good shape but I believe they would have failed eventually. The front seals appeared quite aged and were likely the source of the water incursion.

I did not understand that there were two bearings in the housing until I started the process of changing them. Now I understand that no matter how much I inspect and pack the rear bearing I can not do anything for the front bearing. By switching to oil I can change the lubricant for both bearings.

Thanks for your advice.

 

[KXCam22]

The two bearings and the crush spacer thing. I never thought about that but what you say is very true. Water incursion into the front seal, the spot most likely to leak, could ruin the hidden front bearing while leaving the end visible bearing looking good. The oil bath lubricates (and takes away water) for them both. Cam.

 

[KXCam22]

Just changed the oil yesterday. Oil bath looks good. I def have some water intrusion into one cone and will have to change the seal. Bearings are good and the oil absorbs the water nicely. Cam.

 

[2kwik4u]

Just changed the oil yesterday. Oil bath looks good. I def have some water intrusion into one cone and will have to change the seal. Bearings are good and the oil absorbs the water nicely. Cam.

Thanks for closing the loop and reporting back!

 

[FSH 210 Sport]

Just changed the oil yesterday. Oil bath looks good. I def have some water intrusion into one cone and will have to change the seal. Bearings are good and the oil absorbs the water nicely. Cam.

Did you go with the amsoil again or switch to the mercruiser oil?

What size plugs did you put in the cones?
Did you put loctite in those plugs?