Running problems: chinese 48cc

Discussion in '2-Stroke Engines' started by jocoman, Dec 1, 2008.

  1. jocoman

    jocoman New Member

    I've been having major problems but I now have the bike running tho not well.
    I busted up the magneto, so I have a new coil and magnet in there. The tolerances between magnet and coil are very tight. anyways, it starts up.
    I can run it down the street and power is not too bad. I slow down and it stalls and is very hard to start. I con only start it again by removing the plug, wiping it off, and then put it back in.
    The plug is black and i would say wet.
    So what's wrong?
    maybe the magneto gap is not perfect? Maybe it's a carb problem?
    Any suggestions?

  2. srdavo

    srdavo Active Member

    hmmm....sounds carb related. like it's flowing too much fuel into the engine.

    does your carb float still float?
    does the needle valve shut off the flow of fuel in your carb?
  3. jocoman

    jocoman New Member

    I'll check that first.
    I guess just take the float out and see it if does right?
  4. srdavo

    srdavo Active Member

    yes.... a leaky float will have fuel inside of it.

    while you have the bowl off, you can check the needle valve.

    good luck
  5. When it dies, does it just die ( like some one throw a switch in the off position ) or does it die Slowly losing power.
    how's your mixture,Old, 25 to one ?

  6. jocoman

    jocoman New Member

    I believe the float and needle valve are fine.
    When it dies it just cuts out totally. I reworked the magneto and it is pretty easy now to get it started. I also looked at the spark as I pull the pull starter and the spark is white.
    Not sure what to try next....
    it now is cutting out while idling. it idles for about 60 seconds then dies. Or i take it out and go about 400 yards and then it dies. looks to me like it is chocking. but why?
    where to go next?

    Thanks everone!
  7. alex

    alex Guest

    Is your gas cap venting properly? It could be creating a vaccum and not allowing fuel into the engine after running for a little while.
    Maybe the reason it is working when you take the plug out is because you are giving it enough time to put fuel back into the carb.
  8. jocoman

    jocoman New Member

    I would say the problem is too much fuel as the plugs are black and wet looking.
    Why I don't know....
  9. If the feeling is more like Some one threw a switch and the motor dies I would look at your electrical .
    Re check your wire connections .Temporarily Dis connect kill switch .
    Also check your Spark plug wire connections going to the plug and cdi.
    blue spark is a nice thing.

  10. Mountainman

    Mountainman Active Member

    more blue in that spark ???

    concerned about -- very tight ?

    should not be touching
    a little gap in there is required
    perfect setting is what makes your spark strong

    you mentioned white spark
    wondering if we shouldn't have more blue spark in there ???

    ride that THING
  11. jocoman

    jocoman New Member

    Well, here is where I am now. Re-checked the carb, and i am convinced it is good. I had a sparec CDI and I swapped it in. The bike ran batter(i.e.longer), but then it just cuts out! Starts up and i can keep going. But every once and a while it just cuts out! very frustration. I am back to thinking it is in the magneto. I looked at the spark by grounding to the block and pulling the starter. It was a bright white light, definitely not blue. So what could be wrong with the magneto? Do magets loose their magnetism?
    Thanks everyone
  12. Mountainman

    Mountainman Active Member

    maybe as it heats up tolerance changes between mag and coil

    can you adjust out a little ?

    need some space in THING -- so as to make proper spark

    just guessing here OK ?

    sounds like for sure -- elect problem

    I used to repair a lot of small engins by cleaning rust off coil -- thus better spark
    this is an important area so as to be correct

    ride that THING