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Thread: need some help

  1. #1

    need some help

    I have a 1990 waverunner 500 just got it a few weeks ago. It starts and runs took it to the Lake today it was going fine then it slows down and would only go 5 mph. I also have a 1989 waverunner 650 it wouldn't run that fast also but I found rocks in the back after I got home. I was wandering if anyone can give me advice on what is wrong.


  2. #2
    It sounds like it is in overheat/limp mode...I know at least the 87-89 waverunners/jammers have an overtemp sensor in the head and it puts the CDI in limp mode (limited to ~2000 rpm or so). After letting it cool, does it do the same thing? If so, the sensor may be bad. Not sure what you mean by "rocks in the back", are you talking about in the engine compartment?

  3. #3
    limp mode is possible but you description needs some more input. the wr 500 may not be cooling, or you may have damaged the pump.
    question : does the motor rev. and it goes nowhere? thats a pump issue.
    will it not rev at all??? will it rev when you first start and then stop after you ride ? thats the over heating sensor.
    its hard to figure out a problem without having it in the shop but these are the most common problems.

  4. #4
    Quote Originally Posted by down n dirty neil View Post
    limp mode is possible but you description needs some more input. the wr 500 may not be cooling, or you may have damaged the pump.
    question : does the motor rev. and it goes nowhere? thats a pump issue.
    will it not rev at all??? will it rev when you first start and then stop after you ride ? thats the over heating sensor.
    its hard to figure out a problem without having it in the shop but these are the most common problems.
    Yes I think it was in Limp mode because it gradually slowed down then limped back. When I open up the engine bay it was real hot so I know now its overheating. So with that said what do I check? I don't think the sensor is bad Beacause it did overheat. As for the other ski I want to try it now that I took the rocks out of the tube that spits water out. I owe you both A beer.

    What do I do next?

  5. #5
    So it will still rev just not get up in rpm. I searched the net looks like I need to check the cooling lines for Blockage but I can't find a diagram of this. Any help with this would be great. I live in Point mugu in Oxnard California so if anybody wants to make some money and lives close by let me know.

  6. #6
    now slow down a sec.... does the motor rev or not??? does it sound like a car in neutral???
    im thinking the impeller isnt making pressure there is a cooling line out of the jet pump that goes up the rt side of the ski into the back of the motor. on your ski there isnt a pisser port out the side of the ski so all of the water goes out the tail pipe.
    first look in the jet pump at the impeller are the blades clean and sharp?? is there a gap ? does it look like rocks took a trip in it???
    that ski has a soft aluminum impeller thats easy to destroy no pressure at the pump means no pressure for cooling and no pressure to go baby go. ill bet thats whats up.

  7. #7
    While it very well could be an issue with the pump, I'm thinking that it's more likely to be that something in the cooling system is plugged. Since these skis (AFAIK) have re-purposed outboard engines in them, I don't know if it pulls cooling water from the pump or if it has a separate pump (I feel like it'd be the former). Your best bet might be to try and follow the cooling lines as far as you can, and then disconnect the intake and discharge lines and see if you can run water or compressed air though them. If not, start checking smaller chunks of the system until you find the blockage.

    Still, looking at the impeller is a lot easier than any of that, and if it's chewed up you'll need to replace it anyways.

  8. #8
    Ok thank you very much I followed the cooling lines and one of the hoses that goes into the engine down into the rear of the ski had sand all through it. I unplugged it and had to beat it against the ground to get the sand out. I'll haft to wait until next weekend to try it out but I think I got it fixed. Thank you for all of your input.
    I think there is nothing wrong with the other one because it had rocks lodged into the back where water shoots out. I took them out and I'll try it out.

  9. #9
    If there was that much debris in the hose, there is a good chance that some of the engine cooling passages are blocked as well. It might be a good idea to check all that you can without pulling the motor, I'm not sure how much access there is in that ski. Hopefully it was just that one line though

    As for the other one, do you mean there were rocks in the nozzle? If so, unless you pulled it backwards across a gravel bottom, those rocks got sucked through the impeller and most likely took out the leading edges. A damaged impeller will result in less power and top-end, and possibly cavitation.

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