how much smoke is normal for a 2 stroke?

Discussion in 'Outboard Maintenance' started by sbridewell1, Oct 22, 2014.

  1. sbridewell1

    sbridewell1 I Love!

    Asked this in my intro thread but thought maybe its more appropriate here; After raising my mercury 9.9 about 3 inches to make it even with the bottom of my boat I've noticed that my motor is smoking more; I attribute this to
    1:eek:verheating? (although the pee is only luke warm and the cylinders never got hot to the touch)
    2: too much oil in the mix; i definitely added a couple extra ounces in this mix
    3: clogged exhaust relief hole; noticed this when i got home from fishing all day the small hole was clogged with black gunk
    4: motor is higher so now the smoke that may have always been there is more visible from my seat

    Here is a video of it running
    checked the plugs and they were pretty black looking which makes me hope its just the rich mix that i was burning all day
  2. hferrell87

    hferrell87 Well-Known Member

    Looks to be running well and pissing strong! Have you taken a look at the foot oil? I'm no expert by any means, just really typing aloud. Running the gas/oil too rich can definitely cause more smoke.

    I know I haven't given much advise, but unless there are other contributing problems, I wouldn't think too much is wrong, just maybe a rich mixture. Curious to see what people say...

  3. Brett

    Brett > PRO STAFF <

    A thick cloud of blue smoke is an indication of an oil rich mix,
    or incomplete combustion of the fuel/oil mix, which happens at lower rpms.
    Up to 40% of the fuel pulled into the cylinder is dumped out the exhaust
    when operating at idle speeds in old tech 2 strokes.
  4. sbridewell1

    sbridewell1 I Love!

    Thanks for the input guys, I'm thinking its just the rich mix because this motor runs great for the most part... The only concerning thing is that it does it at wot more than at idle from what I can tell. I did a decarb with seafoam and she's running even smoother now, tons of gunk came out
  5. Lowtidelowlife

    Lowtidelowlife Fine line between recreation and degeneracy.

    Have you checked your plugs after running that cleaner through?
  6. sbridewell1

    sbridewell1 I Love!

    Haven't checked them yet but i'm sure there nasty; i'll plan on replacing them before my next trip out.
  7. Peterson_Marine

    Peterson_Marine I Love!

    Mix ratio for that engine is 50:1.