Carby Carb Flooding

Discussion in '2-Stroke Engines' started by woodyvt, Sep 25, 2008.

  1. woodyvt

    woodyvt New Member

    First, let me say that at 47 years old I have been working on mechanical things all my life and have a pretty fair understanding of internal combustion engines and fluid dynamics. I have done everything from engine/tranny swaps, complete frame changes on modern vehicles to building award winning streetrods. Not to brag, just mentioning my abilities.

    I do accept that I can sometimes miss something that may seem obvious to someone else and also that I am willing to listen and learn.

    Here goes...

    I have been into my carb, disassembled, cleaned, adjusted float, reassembled too many times to count and I cannot stop that darned thing from flooding. I have checked that the float floats, checked that the float shut-off actually shuts of the fuel flow into the carb bowl, I have adjusted the float tangs down as far as to be ridiculous and should just about prevent the carb from getting any fuel at all, I have eyeballed this thing, contemplated every possible flaw that I can think of but it continues to overflow the bowl and flood.

    Yesterday, out of pure desperation, I tweaked the tank fuel petcock to barely a drip, unable to adjust it to idle under those circumstances, but was able to scoot around town for about five miles or so... up to about 25 miles per hour and even had no trouble with a moderate hill with a 36 tooth rear sprocket. That said I'm sure you can appreciate that I think running under those circumstances is a bit silly and this appearantly minor problem should be solvable.

    Today, even though it appears to seal well I am going to replace the fuel bowl gasket and see if that will improve anything.

    So, if anyone has any thoughts or advice regarding this maddening issue, I would be very interested in reading them. Maybe I'm missing something obviously silly so an objective opinion is warranted.... ?

    Thanks in advance.

    P.S. It's a sweet looking ride... Purple Dyno Moto Glide bobber. I'll post pics when I get this carb thing solved.

  2. MotorMac

    MotorMac Member


    Im a marine mechanic and own my own 32 foot Fountain offshore cigarette boat with 2 - 850 HP 520 CI Mercruiser engines with supercharge blowers. I know my engines inside out and am constantly tweaking carbs,, so you are not alone in your frustration with that little bike carb!! I have a Powerking on my bike but its running good.. just a thought as you probably have already checked your jet in the carb,? sometimes they come loose and could cause flooding, they should be locktited in ...Mac
  3. Mountainman

    Mountainman Active Member

    since it sounds as if you are on top of this matter

    just have a thought -- that it's still in the float shut-off area

    not sure why ???

    Ride That Thing - Mountainman
  4. I would check the float for a leak, and filling with fuel and not being able to float, thereby flooding. I have seen a few leaking floats lately. Just a thought......
    Keep us posted, and good luck.......
  5. also.

    Is the motor Tilted extremely forward on the frame toward the Front wheel or back?

    Make sure the tickler ( little button on the side of carb isn't stuck).


  6. arceeguy

    arceeguy Active Member

    I agree with Bob, check out the "tickler". If it is stuck, fuel will just pour into the fuel bowl.

    The little "NT" carb is a model of simplicity and does the job well for what it is. I have tried many different needle positions and have found that if you tune them for good mid-range and top-end, the idle and low speed are on the rich side. Move the clip one notch leaner and the idle/low speed are crisper, but you get light bogging and flat spots from mid-full throttle. Seems that what I need is an "in between" setting. (of course)

    I just keep the needle one step on the rich side, and put up with the "blubbery" low end. Last thing I need is a blown engine from a slightly lean mix. Maybe I'll experiment with some "pocket bike" carbs that have an adjustable idle/low speed circuit.
  7. terrence

    terrence Member

  8. woodyvt

    woodyvt New Member

    I believe that I have figured out most of the problem;

    There are two large lower tangs and two much smaller upper tangs on the fuel float shut-off mechanism. With some closer examination i found that the two smaller upper tangs were not shaped correctly to completely shut off fuel flow into the bowl when the float was at it's highest point. They were not pushing the flow pin up far enough to shut the fuel flow off. I re-arched the upper tangs and I believe that has significantly improved things.

    Enough so that I had my first encounter with the Polizei.

    I know it's somewhat of a "hit and miss" when it comes to the quality of these inexpensive kits and while some of the parts to mine are pretty cheesy, I have been impressed at how durable my little engine is. When all that fuel was rushing into the cylinder and it was revving out to extreme RPMs, I really expected it to blow up many times. Fortunately I've gotten a tough little bugger. I got mine from a guy on craigslist who just lost interest. It was less than half price from new but unopened box. I love craigslist.

    If anyone wants to really know how many factories in China are actually making these kits, check out "" and do a search for motorized bicycle kit. It's amazing.
    Last edited: Sep 26, 2008
  9. arceeguy

    arceeguy Active Member

    Hope your first "run in" with local law enforcement was a pleasant one!

    Glad you figured out your problem. I have built three bikes already and I am working on a 4th. Haven't run into a whacked carb yet, but did run into an engine where the magneto coil had too large of an air gap and wouldn't fire the CDI.

    I think there are less than 10 factories actually making these engine kits, but there are numerous exporters that look like "engine factories" exporting them. Importing engines is not for the faint hearted. I've looked into it, as I'm sure many others here have - and found that you need to order a lot of them and you better be experienced with importing things as a paperwork screw up can cost you thousands. You can also end up with a container load of really poor quality engines. I'll let someone else with more import/export experience handle these things.
  10. dennis

    dennis New Member

    Ive had the same problem after about 800 miles did everyting execpt the tilkler valve. how/ or is best way to unstick one. (ie) the simplest things play with our heads the most.
  11. motorpsycho

    motorpsycho Active Member

    hey dennis dude, this thread is 4 years old and half of those people aren't even on this site any more.
    if you look in the upper left hand corner of the message in the blue bar, you will see the date that it was posted.
    this post is from 9-25-2008!
  12. Al.Fisherman

    Al.Fisherman Active Member

    The date was the first thing I saw opening this thread.... WTH...nothing like digging up the dead. :>)
  13. goodtime65

    goodtime65 Member

    Check to make sure the tickler pin is not hitting the float and also make sure that the tangs on the float arm are not hitting the body because if they do there is not any pressure on the valve
  14. motorpsycho

    motorpsycho Active Member 4...years...old!
  15. HeadSmess

    HeadSmess Well-Known Member

    i bet theres older ones somewhere... im not going on that trip again...omg...


    oh. wait...

    where am i?

    oooo! i know! someone poured battery acid in ya tank!

    may i suggest a new carb :D

    oh...wait. wrong thread.

    what the was i thinking?

    mmmmm, reanimation....


    in answer to the NEW question..."best tickler fix?"

    pair of pliers. pull the silly thing off altogether.
    Last edited: Jan 31, 2012