carb problems!!

Discussion in '2-Stroke Engines' started by clifchub, Oct 1, 2010.

  1. clifchub

    clifchub New Member

    am confused. i'm new, just biult my first bike and am having problems with the carb. i have a Grubee skyhawk gt-5 66cc and the carb floods when i ride, but not if i just let it set with the fuel on, it has to be running to flood, and it wont idle. i use it to get back and forth for work, so any help will be appreicated.. and i live at 5000 ft above sea level if that makes a differance.:confused:

  2. unior

    unior Member

    What exactly do you mean when you say flooding. Is it leaking outside the engine or out a vent? Sounds kinda like a stuck float although I don't know too much about the HT carbs.
  3. JimKamenidis

    JimKamenidis Member

    I had the same prob, you have to set the two pieces of metal that hold the float inside the carb in order that they leave the needle to close the fuel line properly.. After that tight every screw as tight as you can for added safety..
  4. motorpsycho

    motorpsycho Active Member

    sometimes the floats in these carbs (the n-t carbs) will get cocked sideways a little and cause the needle & seat to stay open. this will cause the carb to flood over because the needle & seat can not close to stop the flow of gas going into the carb. bowl.
    sometimes a few taps on the side of the carb float bowl with a plastic handled screwdriver will fix this.
    by tapping the carb bowl, it will cause the float to settle back into the position tht it needs to be in.
    this may be what the problem is, or your float level is way out of adjustment.
    if this is the case them you will need to do what jimkamenidis said.
    this is setting the float level so that the float raises to the top of the bowl when the bowl is full just enough to close the needle & seat.
    if the adjustment is off, the needle & seat will never fully close even when the float bowl is full. or vise versa...if the float level is set too low, the float bowl will never fill up enough and this will cause your eingine to starve for gas, or shut off if the float bowl runs empty too fast.
    in other words, the needle & seat will close when the float bowl is only 1/2 full, and by the time it "asks" for more gas, the bowl is already empty.
    Last edited: Oct 8, 2010
  5. Lazieboy

    Lazieboy Member

    Same issue

    I just went threw that whole thing. motorpsycho said it all. I took it apart and drained the bowl 3 times and then it was better. But i also had an issue where my CDI plug boot was'nt making good contact and not burning all the gas and would foul out plug. so i took boot end off,cut off end of plug wire and re screwed boot in to make good contact. Did'nt get to take a real test ride though. Beer kick in ya know. dont wanna screw up my driving record.
  6. tiki cruiser

    tiki cruiser New Member

    carb flooding

    I started having a similar problem about a month after my first build. I'd turn the petcock on and it would flood within seconds.I took the carb apart and the plastic dougnut they call a float was filled with fuel.It seem's it had a pinhole in it and filled up with fuel making it to heavy to rise and hit the needle valve to shut off gas flow. Went back to bikeberry where I bought my kit and the gave me a new one.Problem solved, so check your float.
  7. HeadSmess

    HeadSmess Well-Known Member

    ive found the flooding that occurs when running and not when sitting is always a matter of float height... just a lil too high, so when you get the vibration of the running engine...needle dont close fully.

    at least i guess thats it cus lowering the level a little always fixes it...
  8. clifchub

    clifchub New Member


    adjusting the float worked on the flooding problem.. but it still wont idle. do i need to get a different jet for a higher altitude? i live at 5000 feet above sea level
  9. HeadSmess

    HeadSmess Well-Known Member

    phwoar, the altitude! im getting vertigo!

    um... theres no idle circuit on the stock carbs :( so changing the one and only jet affects everything... so...possibly not.

    then again... leaning it out some would help.

    ie, go smaller on the jet... in fact, i reccomend it :)

    arrrgh, i can never remember which way you go for alt ! i dont have to worry bout it :p
  10. unior

    unior Member

    Your right, there is less air at altitude so he needs less fuel.

    Your head isn't too much a mess afterall. :helmet:
  11. Skyliner70cc

    Skyliner70cc Active Member

    Although the engine runs slightly rich, I've never had to rejet a HT engine at my 6600 foot elevation. In fact, when I added a tuned exhaust from SBP, I had to add a larger jet.

    Its possible new carbs are jetted larger and elevation gains would require rejetting.

    SBP sells new jets.
  12. HeadSmess

    HeadSmess Well-Known Member


    tuned pipes change tune depending on elevation cus of density of air! and the speed of sound then changes... and they depend on the speed of sound... then the exhaust gas temp is different too! changing the speed again!

    meh, probably very minor...

    just thought of that :D smart, huh?
  13. JimKamenidis

    JimKamenidis Member

    I would like some help!
    I have an ht engine and it was running fine but I thought it was a little too rich at idle so I changed the needle setting at the leanest and I think I have lost some power althought the engine still runs fine, can this be due to the leaner setting???