Is this normal for a new engine?

Discussion in '2-Stroke Engines' started by Corey, May 27, 2011.

  1. Corey

    Corey New Member

    Hey, I've had my 66cc 2 Stroke for about a week now and have done probably 90Km's on it, it can be kind of jolty sometimes and doesn't really run smooth, other times it will run quite smooth.
    Is that called bogging?
    Is it because its not a great engine?
    Will it run smoother when its finished the break in period?
    All answers appreciated.
    Thanks, Corey.
     

  2. Al.Fisherman

    Al.Fisherman Active Member

    Do you have the stock plug, wire and boot. Have you moved the clip on the needle in the carburetor.
     
  3. Corey

    Corey New Member

    Yeah its all stock and nah I havent done that
     
  4. jaguar

    jaguar Well-Known Member

    Not running smooth is due to the mixture being too rich. You need to solder shut the main jet and drill a hole there that is a smaller size. Click onto my link for details. Also make sure the carbs filter cover has enough holes in it to breath good at high rpm's. If not then that can cause it to run rich.
     
  5. motorpsycho

    motorpsycho Active Member

    ohhh, suggesting that a newb. solder and drill out a main jet is a bold move, especially if he is unfamiliar with carbs and jetting. (I am assuming that he doesn't know much about carbs based on your description of the problem).
    a SLIGHT change in the main jet hole size can make the engine run really lean and burn up the piston.
    you have to know what you're doing, and what you're dealing with when it comes to re-drilling a main jet.
    I mean a TINY difference in hole size can make a huge change. on the other hand, he may know exactly what he's doing, and since jaguar posted instructions, maybe i am just assuming too much.

    More than likely, i would blame the non smooth running on the 16:1 gas/oil ratio that you're probably running.
    In my opinion you should run it through it's break in period (16:1 is too much, 20:1 is better for break in) and after the break in, then start playing with the carb.
    but, if you have no clue about jetting and tuning a carb, then you will need to do some research and find out what you're getting into. An improperly jetted carb can kill one of these engines in no time.
    Just my opinion.
     
  6. jaguar

    jaguar Well-Known Member

    I agree with you mostly but with a micro drill bit set if you determine the stock size and then select a bit the next size smaller there is no huge jump that would be from "too rich" to "too lean". More than likely you'd have to go thru the same process 2-3 times to find the just-right size.
    He's running too rich and it isn't because of the 16:1 ratio. That much oil is actually leaner than a 20:1 ratio.
    Newbies learn by doing, following the lead of others. It takes no research or a college degree to remove the main jet, heat it with a candle flame, melt solder (from Radio Shack) into the hole, and then carefully drill a new hole into it. Just be careful not to break the micro bit. The drill speed should be minimal.
     
  7. motorpsycho

    motorpsycho Active Member

    yep you're right...it aint rocket science.
     
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