carberetor problems!

[harry11]

I own a simple 50cc mini dirtbike (big wheel and no mods) and just recently when i accelerate it makes a low pitch hummm sound then cuts out i have been playing with the mixture screw that might of made it worst, i have also hosed it clean that might have caused problems it is now also leaking fuel through the waste pipe if there is any idea's how to fix this problem please help me

the pic is of my bikes carb

 

[harry11]

by the way this is the bike

 

[Cactus Jack]

2 smoke ...

A 2 stroke ... There's a drain screw right at the bottom of the carb's float bowl and when you unscrew it , fuel comes out of the lowest hose ... It's there to drain water and dirt out of the float bowl ... Sometimes they can simply be loose and just need re tightening ...

IF the leaking persists after checking the above ...You'll have to clean the float bowl out and check that there's no junk (bits of plastic and crap in the fuel line) that came from the tank and is now jamming the float needle valve open ... IF there's anything in the fuel line ... you'll have to remove the float bowl , float pivot pin , float arm , float needle and spring ... then remove the fuel line off the tank and blow it out ... IF it still leaks after doing that ... then you're going to have to adjust the float level ...

Check out the PWK post for info on how to adjust the float arm ...

 

[harry11]

that still does not solve the low pitch humming sound then cutting out is there a original position of mixture screw e.g.screw until finger tight then screw anti-clockwise so many times to get to factory position or do i have to disemble the carb to see if there's any junk inside. pls help

 

[2freeq]

i dont think that particular carby has a air fuel mixture screw, the ones i`ve seen the same as that it only has one screw and that the idle screw.
if the carby is blocked the noises you hear could be somthing to do with it starving fuel, i`d try what cactus jack said first and let us know how you go.

 

[harry11]

i tried everything that cactus jack had described and it now is incredible in the way that the acceleration is very pleasing and the engine is making all the correct sounds. i would just like to thank you cactus jack for your extreamly helpful and knolagable awnser to my problem