Reconnecting Oil Pump on 97 Yam GP760

frozenokie

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Feb 4, 2008
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Bought a new oil pump for this waverunner. Lines are clear - not blocked. Need to know the best way to get the oil feeding into the air intake. It obviously takes too long waiting for it to "climb" its way through the hoses up to the intake. My guess is to unhook each hose one at a time and manually fill them and then reconnect. Is this the best way?

Also, while watching the oil being pumped for a couple seconds with motor running, it seemed to be a very slow pulsation type movement. Is this the way it's supposed to work?

Don't really want to go back to pre-mixing, but I will if I have to. I just like the convenience of having the oil injected and besides... I've never had problems with oil pumps in the past like some riders seem to have. I also don't want to risk this motor if it doesn't pump correctly - I just don't know how to tell if it is pumping right or not???

Can anyone tell me what signs to look for in a correct oil pump flow and in a malfunctioning flow (versus the obvious of no flow at all)?
 

dannyual767

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May 15, 2010
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273
Re: Reconnecting Oil Pump on 97 Yam GP760

I'm experienced with this since I just redid the oil lines in both of my skies earlier this week. The failure point of Yamaha PWC oil injection systems is usually an oil line coming disconnected from it's fitting. This happens either because the zip tie doesn't hold on tight enough to the old hose or the old hose shrinks in length and pulls off. Probably plenty of other reasons as well. The best thing is to replace the old oil lines with new and use superior Oetiker clamps like I did. Some people say that they've had good luck with new zip ties on new lines. BTW, I purchased all of my hose, clamps and clamp tool from McMaster Carr.

You said that you bought a new oil pump so I'm going to assume your original went bad. From what I've read on the PWC forums that I frequent, the oil pumps are extremely reliable and I'm still running both originals (see my signature.)

I used a plastic syringe to inject oil into the lines. Each line to each cylinder had a one-way check valve that I reused. I'm going to assume that you have the same. The plastic syringe will get the oil all the way into the line. Try to have no air bubbles if possible.

After my work, I ran the skis on the trailer with the garden hose hooked up. I kept the flame arresters off so I could watch the oil slowly pulsing into the carbs. My GP1200 lines had air bubbles and I could see that the oil pump slowly pulses the oil up the lines like you saw.
 

frozenokie

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Feb 4, 2008
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309
Re: Reconnecting Oil Pump on 97 Yam GP760

I used new Yamaha oil lines from the dealer. I bought the bike from a guy who said the he was premixing the gas. So when I inspected the old pump, I realized why. The outer body casing was broken where the worm gear is. I also bought new check valves, but I couldn't get any oil to pas throught them - yes, I know to follow the flow direction arrow, but for some reason couldn't get them to work. I called dealer to return them, but you know how they are, once you connect them, they're yours.

So, what I did was take the check valves out completly, but am worried about what significance they have in oil supply. My guess is to hold the oil in place while the bike is not being ridden and then upon next start-up, oil is assured to be right at the oil exit in the intake where it needs to be. I thought I would try it without and just keep an eye on the oil level in the lines bofore I start it. Right now, I have zip ties for clamps. Do you mean the type of clamp that is plastic and squeezed with pliers to latch tight. Look like a ring with teeth grooves???

Thanks for replying - I feel better about the oil flow this bike shows when running - seems to be just right.

Can I use a different style check valve instead of trying the same old yamaha dealer "screw you" move? Those things cost me $30 a piece and ponly for them to be trash :mad:

Thanks dannyual767!
 

dannyual767

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Re: Reconnecting Oil Pump on 97 Yam GP760

Yes, they are about $30 each from the dealer. What a rip off. McMaster Carr has some for less than $4 each. Probably the same thing. Scroll to the bottom of this page to have a look: http://www.mcmaster.com/#pvc-check-valves/=dpqn3a

When I redid my lines last week, I noticed that one of my check valves on the GP1200 was very hard to push oil through with the syringe. The other two were fine and both of the check valves on the Raider were fine. I did the work on the GP1200 first and had to stop midway through the work. I had already primed the lines with the syringe when I had to stop. Later in the day when I came back to finish, I noticed that oil had flowed backwards through two of the check valves :confused: . Instead of removing and repriming the lines, I decided to manually inject oil into each of the carbs (with the syringe) while the ski was running and the oil pump was pushing oil into the lines. I know I got way more oil into the cylinders than I needed because I was seriously fogging for mosquitoes!

I've since checked the oil lines and they seem to be holding oil and it's not flowing backwards any more.

I've been trying to post the link for the Oetiker clamps from McMaster but after I post and check it, it just goes to a generic clamp page. If you go to McMaster Carr, they are listed under "gap-free pinch with tongue and groove."
 

frozenokie

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Feb 4, 2008
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Re: Reconnecting Oil Pump on 97 Yam GP760

Thanks for the links and information dannyual767. I'll get those valves from McMaster/Carr. Funny thing is I'm used to using the M/C catalog for engineering purposes - but never thought I would be using it to fix my waverunner :D

Will repost when it's all done for an update.

Many thanks -
 

frozenokie

Petty Officer 1st Class
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Feb 4, 2008
Messages
309
Re: Reconnecting Oil Pump on 97 Yam GP760

McMaster Carr has some for less than $4 each. Probably the same thing. Scroll to the bottom of this page to have a look: http://www.mcmaster.com/#pvc-check-valves/=dpqn3a

I looked ther and have a question. Which seat did you use:
Polypropylene or Nylon?
The Buna-N or fluoroelastomer seat?

Just want to use the same thing you did. My guess would be Nylon with a fluoroelastomer seat.
 

dannyual767

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May 15, 2010
Messages
273
Re: Reconnecting Oil Pump on 97 Yam GP760

frozen, I replaced my original oil lines with brand new McMaster Tygon and used their USA made "gap-free pinch clamps with tongue and groove" (Oetiker) to cinch things up. I reused my original check valves but found that one was very difficult to push oil through. Not only that but two of them allowed oil to back-flow which they are not supposed to do.

At that point, I thought about replacing them with new Yami stuff until I saw how much the OEM stuff costs. That's when I started looking to McMaser Carr for some substitutes. At this time, I haven't bought any check valves so your guess is as good as mine on which ones.
 
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