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2005 90HP 2 stroke smokes on startup

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  • 2005 90HP 2 stroke smokes on startup

    I have twin 90s and one of them has started to smoke quite a lot on starting, after a couple of minutes it clears and runs perfectly. They both use the same EXOL oil (TC-W3 spec) that I have been using for years and the other engine only smokes a little at start up as you would expect. I have cleaned the carbs with spray cleaner - done while running by spraying into the air intake which doesn't appear to make any difference. Both engines consume, as far as I can determine, the same amount of 2 stroke oil. Once running at idle both engines are fine, its just purely on starting - anything to be worried about?

  • #2
    My 1999 C90 2 stroke outboard always smokes some on start up....just part of the 2 stroke experience....no problem so far....helps keep the mosquitoes down!

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    • #3
      I've got twins as well with one being at lot more of a smoker on start up. It's also the one that drips more oil when tilted so I think it's related to check valve(s) not closing. When it drips into air intake it gets sucked into cabs and goes down crankcase tubes as well.

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      • #4
        Originally posted by CharlieH View Post
        I have cleaned the carbs with spray cleaner - done while running by spraying into the air intake which doesn't appear to make any difference.
        2 stroke smoke at start up is no biggie, quite typical. Perhaps it's running a little rich though. But what you're doing here ^^^ is a big no no. Not only does carb spray not clean the carbs, but it also eats away at the oil lubing the carbs, so to speak. Carb cleaning entails pulling carbs, opening, removing and clearing jets, checking float height, and replacing kit if need be.
        Jason
        1998 S115TLRW + 1976 Aquasport 170

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        • #5
          Originally posted by BQUICK View Post
          I've got twins as well with one being at lot more of a smoker on start up. It's also the one that drips more oil when tilted so I think it's related to check valve(s) not closing. When it drips into air intake it gets sucked into cabs and goes down crankcase tubes as well.
          This is also exactly what I have on the smokey engine - how do you inspect the check valves?

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          • #6
            I have used a syringe to move air or oil back and forth, check valve should only allow flow one way

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