02-14-2008, 03:40 PM #1
How do you change pump lube from grease to oil
I want to change the lube in my drive pump from grease to oil, for less resistance. Is this a tricky thing to do? Has anyone done this?
02-14-2008, 04:47 PM #2
The pump has sealed bearings, There is no grease or oil that needs, or can be changed.
02-14-2008, 04:53 PM #3
I think that only seadoos have oil in the jet pump for the bearings
02-14-2008, 05:41 PM #4
aaahhhhh.... that sucks... oh well.. can't blame a guy for try'n....
Thanks for the info..
02-14-2008, 05:52 PM #5
That's not entirely true. If you are good with a small pick, you can remove the seal and expose the balls. Do that to the bearings, reinstall them and lube away
Search the yamaha side for various lubes and choose the one that you feel is best. I prefer this http://www.amsoil.com/storefront/agm.aspx?zo=152062
02-14-2008, 06:40 PM #6
- Join Date
- Jul 2007
- near Toronto, Canada
I would question whether the speed or acceleration difference could even be measured. It takes a big power increase to measurably increase real world speed, and I am doubtful that there is that much power loss in the pump bearings.
Unlike an automobile differential, there are no gear tooth sliding friction losses involved, just the bearings keeping the stub shaft centered in the pump stator. Impeller thrust loads are delivered by the drive shaft to the engine coupler, so the pump bearing is not really heavily loaded.
There is some viscous turning resistance when the grease is cold, but as bearing speed increases, grease tends to become less viscous, more like an oil.
I would expect most of the gains to be had (and some will be modest) are where the water flow contacts the hull and jet pump.
Improved water flow = more speed.
Ride plate, impeller, intake grate, hull attitude at speed (pump wedge and rider position) - these are the traditional areas of focus, outside of engine power upgrades (which are not yet available for Fitch motors).
Where do you need to go with your speed quest?
How much faster?
How much money do you want to spend getting there?
About $10,000 will get you to about 80mph, and you would still have your current boat unchanged.
Or buy the motor for $3,000
02-14-2008, 06:40 PM #7
thanks addicted.. yamaha.. that's right, that is the kind of ski my buddy has. .he did this (and a number of other things) to get a little more speed. I kind of figured a pump is a pump and we could do the same on a polaris..
02-14-2008, 07:13 PM #8
Hey K... I have thought about getting one of the newer faster ski's and probably will.. but to not modify... what the heck kind of fun is that.. to not have something break down or not work like it should.. i wouldn't know what to do with the extra time......
I really don't know what kind of change it would make.. i have modded my ride plate a bit by plaining it out.. and have a better impeller on it.. i can see the logic behind decreasing the resistance in the pump to make the motor move water easier.. or faster.. but i could be wrong....I have an extra pump, so what the heck....
Besides, with the luck i have with this ski it will be interesting to see what really happens.. well, i have to get the beast running again first... i am getting ahead of myself...
02-14-2008, 07:49 PM #9
A while back(maybe a year or so ago) I thought about trying out ceramic bearings, but with the thought of the high thrust loads on it, the bearing would wear out real fast. But i can see vegas why someone might want to go to oil just because of less resistance
02-14-2008, 09:47 PM #10
It's not a dramatic difference, but anytime you reduce friction, you increase horsepower. On my raider, I got noticeably quicker revs, and about 50 rpm's on top. Doesn't sound like alot, but combine that with a bunch of other little things and you are building solid speed.
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