1996 2-Stroke Evinrude 9.9 Won't Idle Reliably

Discussion in 'Outboards' started by nbehlman, Sep 21, 2014.

  1. nbehlman
    Joined: Aug 2011
    Posts: 63
    Likes: 3, Points: 8, Legacy Rep: 50
    Location: CT

    nbehlman Junior Member

    I recently pulled an old wooden skiff out of my mom's garage that had been sitting for about 9 years. It has a 1996 evinrude 9.9 short shaft on it. It was only used for two seasons when I was a kid and it always ran great. After 9 years, it started on the fourth pull and ran as if it was brand new (used water muffs in the backyard). I took it out on the connecticut river and had no problems whatsoever. The next time I took it out, it would stall when I tried to idle. I was having trouble with a crappy fuel line from amazon, so I replaced the fittings and primer bulb. That took care of the leaks, but it still wouldn't idle. I cleaned out the carb and fuel pump and installed rebuild kits for both. I installed new fuel lines in the motor. I installed new spark plugs. Still wouldn't idle no matter what I did with the mixture screw. I set the idle screw to give it a little more throttle at idle speed and that seemed to help it idle on the water muffs. I put the boat in the water and it wouldn't idle for more than a couple seconds. If I quickly put it in gear and give it the throttle, I can motor around all day long. As soon as I cut back to idle, it's dead again. I'm quite confused. I don't think there's anything left in the fuel circuit to replace except the fitting on the engine side. I don't understand why it ran so beautifully the first day and now it wont't idle. It takes a lot more effort to start it as we'll. I find that if I keep playing with the choke, I can keep it alive. I choke it until it starts sputtering out, then I unchoke it and it revs up for a second before sputtering out again, then choke again, etc, etc. Seems too easy to blame the ethanol since it ran fine at first. I've replaced all the gaskets in the carb and fuel pump and they looked fine. I am at an utter loss for what the problem is. Can anyone help?
  2. gonzo
    Joined: Aug 2002
    Posts: 15,773
    Likes: 1,199, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    Get the manual and check the link and sync. That may be the problem.
  3. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 490, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Well, you description seems to suggest she's running too lean, but it might just be a chunk of ethanol deteriorated fuel line. I clean carbs out all the time and these small carburetors have equally as small passages in them, so a tiny little chunk of rubber can plug or partly plug the low speed mixture passages. The hoses break down and the inside of them spit out little hunks of rubber, some you can barely see.

    I'd check the tune first, as Gonzo suggested and get it to spec (you'll need a manual). Sync up the carbs and see where you stand.
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