Help me diagnose 2 stroke problem

Discussion in '2-Stroke Engines' started by cobrafreak, Jan 7, 2011.

  1. cobrafreak

    cobrafreak New Member

    I'm confounded and don't know what to do at this point. 2 stroke Skyhawk has been running great. Currently has 120 psi of compression. I have the C-clip all the way up on the highest needle jet slot and I'm still getting oily wet plugs after an attempted test start. Just no combustion. No carburetor obstructions. Fresh gas. Proper oil mix. I'm getting good fuel flow into the float bowel. No clogged lines. Proper gas tank ventilation. fuel cap is not obstructed. I checked the main jet for any obstructions, none. Cleaned it out anyway. My Carburetor to intake to engine fit is tight. I am switching spark plugs, no results. I am getting a bright blue spark visible in a well lit garage, so the voltage is there. Cleaned the air filter. It was not dirty but did it anyway. I even took the exhaust completely off to see whether or not it was clogged. It wasn't.

    So I have:

    -fuel+air+spark+compression, but no combustion. I ordered a second motor and when I get it I will tear into this one if necessary to see what is up with it. The only thing I can think of is that maybe the coil is not sparking enough for combustion even though it looks bright and visible to me. :confused:

    One clue that might be useful to you but means nothing to me is that yesterday and today while attempting to start it up it would have a single loud "POP". It has never done this before. Not an air escape pop but a combustion pop, but without combustion. So I'm leaning toward Ignition, but not really sure. Any help would be appreciated.

  2. GearNut

    GearNut Active Member

    Seeing as you have all ready changed out the spark plug, I go with: bad CDI unit, bad spark plug wire or bad spark plug cap.
    It is possible to have an ignition give a good, bright spark outside of the engine and still be too weak to spark under the strain of compression when everything is installed to run.
  3. Bobbyoutback

    Bobbyoutback Member

    Check out the float level in the carby .

    Good Luck
  4. cobrafreak

    cobrafreak New Member

    I went to the local auto parts store and got a spark plug wire set and installed it. The engine fired right up! Lesson learned. Just because you see a bright spark does not mean it is enough to support combustion. Thank you guys.
  5. goodtime65

    goodtime65 Member

    If you are getting spark but feel that it is an ignition problem it is possible that your magnet is on backwards, I have ran into this problem a few times. You can have a quick look by taking off the nut and washer, turn your engine over so that the flats of the magnet are on the top and bottom with the keyway pointing upwards. The keyway should be in the one o'clock position, not the eleven. Take a quick look and see if this is your problem
  6. GearNut

    GearNut Active Member

    If the magnetic rotor was installed backwards the spark would occur at the wrong time and the engine would not run at all. At best you would get "coughing and sneezing" out of the engine.
  7. GearNut

    GearNut Active Member

    Congratulations on your repair, cobrafreak!