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  1. #1
    mike2's Avatar
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    Need alittle help for 98 785 pro

    I purchased a 98 785 pro almost 2yrs ago with a bad cylinder. I have since rebuilt the entire top end with new cylinders, replaced all the fuel lines and rebuilt the carburetors. The ski will run great for about a minute or 2 then die. It then has to be cranked for a bit with the choke closed in order to restart and then runs great again for a min. or 2. Im kinda stumped on this and ended up putting the ski away last year because I relocated to S. Korea for work. I am coming home next week after a year of being away and would like any advise to get this ski back on the water. I was thinking of maybe upgrading the carburetors because before I rebuilt them it did the same thing. Only other thing I can think of is my crankcase is leaking but wanted to ask before pulling the engine. Thanks


  2. #2
    Moderator beerdart's Avatar
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    Check the fuel tank venting system.

  3. #3
    mike2's Avatar
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    I can't recall if I checked it. Usually I don't mess with the vent lines on skis I have rebuilt so I probably didn't change it on this one either. That will be the first thing I will check, thanks.

  4. #4
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by mike2 View Post
    I can't recall if I checked it. Usually I don't mess with the vent lines on skis I have rebuilt so I probably didn't change it on this one either. That will be the first thing I will check, thanks.
    Did you clean out the fuel tank last time? If there is contamination or perhaps some water in the bottom of the tank, it will get sucked into the fuel pick up inside the tank. Fuel tank must be 100% clean inside.

    Do you now have one year old gasoline in the fuel tank< or even older? Drain the old fuel out, make sure the tank is clean. Also check the fuel filler neck and gas cap for cracks or damage that might allow water in.

    My signature links cover a bunch of other common maintenance items, including the fuel shut-off valve o-rings. You really need the entire fuel system to be 100% perfect.

    A quick test for a fuel tank venting problem is to crack the gas cap open, note how much pressure (or vacuum) is relieved, then close it up and try the engine. If the air pressure release 'fixes' the problem then the venting has a problem.

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