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  1. #1

    Problem with one of my Waverunner WR500Q

    A few weeks ago one of my waverunners started to idle rough and bog when taking off until mid or WOT is reached. Once cruising it's fine, but sometimes when it stalls I have to choke it to get it running, then quickly push it in to get going. I rebuilt the carburetor snd the symptoms didn't change. My filters are all good and bolts are tight on the carb to intake manifold. I adjusted the carb as the manual said and the low speed idle is way out of specs to maintain best idle. I've tried it 3/4 to 1-1/2 turns as the manual says and it won't even run. I'm probably CCW 3 turns. The fast idle is normal, about 3/4 to 1 turn CCW. If I start it on dry land with no water connected to the flush inlet, it runs fine but as soon as I turn on the water it bogs. This should be a tell tale, but I don't know where to look. What do the experts on this forum think.

  2. #2
    Old Ski Insanity w/rpm500's Avatar
    Join Date
    Aug 2005
    Crystal River Fl
    sounds to me your not getting fuel thru the system (clogged in tank filters)or is pulling air in some where... check your fuel lines for cracks and also your fuel gate valve..
    check your pulse line itegrity on the block to make sure the fuel diaph is getting good vac. to operate properly..
    check for a vac leak on the intake to carb flange and at the manifold to block surface..
    does it do it on reserve also?
    what does it do on an isolated 1 gallon tank?

  3. #3
    In tank filters have been replaced. I'll check everything for cracks, I hadn't considered a vac leak. I did try it on reserve and same thing. I haven't tried an isolated 1 gallon tank, that will be next. Thanks, this gives me some homework.

    By the way, how is it a fuel problem only with water connected to the flush inlet? It does run fine with no water connected. I can see being in the water because of the extra load on the impeller, but a water hose on the flush valve shouldn't increase the load.

  4. #4
    Today I checked the check valve to the tank and it was functioning. I also checked the compression and both were about 135psi. Then I tested the vacuum from the manifold to the carb with a T adaptor and it was 5-6psi at idle, and so was my good ski. I then started it up and it idled fine with water connected and only bogged a little when I goosed the throttle. This is with the slow idle screw at least 3 turns out. When I go to 1-1.5 turns it stalls.

  5. #5
    yankejr's Avatar
    Join Date
    May 2012
    Ocala, Fl
    Did you change the needle arm spring when you rebuilt the carb, you may have to high of pop off pressure, and trying to compensate with low speed screw.

  6. #6
    There wasn't a comparable spring in the kit I had, but the one in there was in tact. The ski was running great one day and started doing this out of the blue. I did pull apart the needle arm assembly and reassemble it to be sure there weren't any broken parts or gunk in there though. I think I'm going to buy a used carb from ebay and try that. Thanks for all of the help.

    I do have a change in symptoms. I took it out yesterday after my other testing yesterday and it ran great for the first 15 minutes. My daughter got on it it started doing it again. Then I got on and it worked fine. The difference was I was either at WOT or off, I don't do much with this ski at partial throttle or idle. I timed the failure to about 15 seconds at idle, then it starts acting up. If I'm at WOT most of the time and very little idle, it works fine. Again, this is with the slow idle at 3 turns CCW, it won't run at 1 to 1.5 or anything close.

  7. #7
    I can look to see if I have anything in my service manual when I get home. I remember getting a manual for your ski when I bought mine.

  8. #8
    Actually I purchased a used carb from an 89 off of ebay and it runs great. Thanks any way.

  9. #9
    wow, well great! Now just to go through that carb and you'll have a spare!

  10. #10

    Join Date
    Aug 2010
    South Florida, USA
    I'm sure you've tried it but I to had this problem after rebuilding carbs. Couldn't find the problem until I found that replacing the spark plugs regularly finally solved my problem. I have a 760 Raider and as we all know these things smoke up the joint if we still use the oil pump. Since replacing the spark plugs on a regular basis I don't have the bogging problem anymore. Just a thought...

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