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  1. #1
    Zooky's Avatar
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    1996 SLX 780 bogs when cold

    I have a 1996 SLX 780 that bogs when cold and at first try to apply throttle to it. Have to repeatedly tap the throttle to get the ski to go past idle. It usually dies once or twice before it will accept the throttle. Once it accepts the throttle it will run all day without any problems. What can cause this "cold natured" problem. My compression is 145 to 150 across the cylinders. I have checked all fuel related areas. I use 93 octane and YamaLube tcw3 2m. This ski will run 58-60 mph without a problem after I get past the "cold natured" issue.


  2. #2
    I'm a noob but from the knowledge I've soaked up I get the impression that's the nature of the beast. Let 'er fully warm up and then wring it out.

  3. #3
    Zooky's Avatar
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    1996 SLX 780 bogs when throtle is applied when cold

    Thanks for the suggestion, but running it after a session of the "cold natured" problem is what I am doing now. I really would like to solve this problem so that the ski will perform as it used to.
    Anyone else with any suggestions?

  4. #4
    ph2ocraft's Avatar
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    Have you performed a plug chop to verify you aren't too lean?
    Try opening the lows 1/4 turn and see if that helps. If it does, that's another indication of a lean running condition.
    I'd take the carbs out and check for garbage in them, pay particular attention to the filters.
    The ring floating in the seperator??

  5. #5
    Hey isnt that compression and speed a little high, ok maybe alot high?? Help me ph, mine were 120 after a full rebuild.. Top speed was 48-52..

  6. #6
    ph2ocraft's Avatar
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    Quote Originally Posted by gvnitup View Post
    Hey isnt that compression and speed a little high, ok maybe alot high?? Help me ph, mine were 120 after a full rebuild.. Top speed was 48-52..
    His compression gauge is probably off but it's more important that the numbers be within 10%, which they are.
    The speed is probably off the dreamometer, some are very acurate,others aren't. When they read high on the older system it's usually do to a partially blocked or kinked line whick creates higher pressure and an increased reading.

  7. #7
    Zooky's Avatar
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    The plugs have dark carbon deposits on them. after a fw days of running the deposit buildup is enough that you can scrap it off with your finger nail. The ski still bogs when cold with new plugs. The ski idles just fine. No missing or any unusual sounds, until you apply the throttle. As I said before, once I get it accept the throttle I have no more problems that day.

    I will adjust the lows to see if they make any difference.
    Next will be the carbs. Where is a good place to by rebuild kits for my carbs?

    Thanks for the help!

  8. #8
    Your the man PH thanks for correcting my confusion..

  9. #9
    Zooky, just my two cents but from experience. It sounds like the filter, or the low speed jet may be getting stopped up.. The way I have found to identify this was when you try to throttle up, pull the choke out while you go full throttle, then push it back in fast. If the ski takes off, then you have a low speed jet bumming up.. I purchased all my rebuild kits from Al at atlantic powersports. He has always given me a great deal. He is very trustworthy also.. I have his number, but they advertise on here also though.. oh P>S> make sure you use oe parts the aftermarket are crap..

  10. #10
    Zooky's Avatar
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    Quote Originally Posted by ph2ocraft View Post
    His compression gauge is probably off but it's more important that the numbers be within 10%, which they are.
    The speed is probably off the dreamometer, some are very acurate,others aren't. When they read high on the older system it's usually do to a partially blocked or kinked line whick creates higher pressure and an increased reading.
    ________________________________________

    Your dreamland is not real. I have clocked the ski several times and once with a radar gun. I weigh 205 pounds and I get 58mph. My grandson weighs 170 pounds and gets 60mph. In both incidents the ski was still climbing in speed, although ever so slowly. I too thought the compression was high, but used two different gauges to check it. They were within a psi of each other.

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