Lean Sneeze?

Discussion in 'Outboard Maintenance' started by MariettaMike, Oct 18, 2013.

  1. MariettaMike

    MariettaMike Wish'n I was Fish'n!

    After a whole summer of running flawlessly, my 2002 Yamaha 90 2 stroke started sneezing at idle again when I got back to the dock last Saturday. It is my understanding that this is caused by lean conditions due to obstructions in the fuel idle passages of the carburetor(s).

    When this problem happened last winter I disassembled, cleaned, and reassembled all three carburetors the problem went away for the last nine months. (I didn't replace any parts, gaskets, or diaphragms.)

    Not wanting to do that all over again I am wondering if there is any "trick of the trade" to remedy this problem without the full disassemble cleaning?
  2. Brett

    Brett > PRO STAFF <

    I suppose you could try a fuel treatment and hope it gets better.
    I've gotten to the point that I expect to have to pull the carb on my 5 hp Nissan
    at least once a year in order to soak the carb body in isopropyl to remove varnish build up.
    Not enough running time to clean out the passages as the flats are only a few minutes from the ramp.

  3. danville_marine

    danville_marine I Love microskiff.com!

    when im in a pinch i'll open throttle up while running shove a rag in the throat it might suck it out
  4. flyfshrmn82

    flyfshrmn82 Well-Known Member

    I've had a couple fishing buddies (one with a 60yami 4stk, the other with a 30tohatsu 4stk) who had rough sneezing engines at idle. Startron seemed to cure the idle issue....
  5. MariettaMike

    MariettaMike Wish'n I was Fish'n!

    UPDATE: I ran the idle screws closed one cylinder at a time with the engine running to determine the top carb was the problem. Removed that idle screw completely and replaced. Lean sneeze is gone, and engine has idled smoothly ever since last October.

    Apparently I must have missed one small piece of debris when I cleaned the carbs last summer.