cns carb, gas running out of overflow tube

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patricklogsdon

New Member
Jul 9, 2012
7
0
0
Louisville KY
OK, this concerns the "new" CNS carb that came with my 66/80cc engine kit. Why all of a sudden does this happen?? Gas will just start coming out of the plastic tube that is attached to the bowl. I took the bowl off and looked at the float....it seemed ok...GGRRRR...anyone else having this problem? Should I ask for a new carb? This carb has LESS than an hour run time on it!! Please reply to this forum and/or [email protected].
THANKS!!!
 

nightcruiser

New Member
Mar 25, 2011
1,180
2
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USA
Because the carb on most bikes does not sit level a float adjustment is usually a good idea. If you have fuel coming out the overflow (tube coming from the bottom of the carb) then you either need to do a float adjustment to lower the fuel level in the bowl, or your needle valve is stuck open, or the needle is missing or installed backward (pointed end goes into the valve).
To adjust the float to hold a lower fuel level in the bowl, bend the tab upward slightly so it pushes the needle closed when the float is sitting lower in the bowl.
Should be as simple as cleaning the needle valve and/or assembling it correctly, or bending the tab on the float a tad to fix you up....
 

Al.Fisherman

New Member
Sep 9, 2009
1,966
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Calera, Alabama
If you are not familiar with carburetors, if so I wouldn't waste too much time on the CNS. Go buy a NT or NT speed carburetor. I have many years working on carburetors, and for the price, I wouldn't waste my time working on one to get running correctly. Some have I wouldn't, as I don't believe there is much increased performance...but that's me.
 

nightcruiser

New Member
Mar 25, 2011
1,180
2
0
USA
If you are not familiar with carburetors, if so I wouldn't waste too much time on the CNS. Go buy a NT or NT speed carburetor. I have many years working on carburetors, and for the price, I wouldn't waste my time working on one to get running correctly. Some have I wouldn't, as I don't believe there is much increased performance...but that's me.
You know we have a differing opinion on the CNS carb Al. I knew nothing at all about carbs when I started and I was able to tune my CNS carb to run great in short order, so I don't really understand why someone with all your experience would poo-poo the idea of tuning one. There are LOTS of people riding around on CNS carbs now, it's not the old days when they were rare and unfamiliar...
At any rate, a very simple float adjustment is the first step, and sometimes only step required to get a CNS carb tuned up. I know the NT carb is cheap, but it's not magic, people still need to tune them... Since he already has a CNS carb why not tweak the float tang a bit and see how she runs rather than buying a new carb, swapping throttle cables etc?