jonway yy250t leaking fuel from carb while running By rcapete007 (Read 2,659 times)

[Alleyoop]

Great, that will tell all.
Alleyoop

[Bashan]

[tvnacman]

check for fuel in the vac line or damp wet vac ines .

John

[rcapete007]

Its pouring out the overflow hose for sure. No gas in the vacuum lines.

[Alleyoop]

Time to take the carb off and check the float and clean out the fuel inlet from the inside also check if the valve which usually have a pointed rubber tip is not damanged.
Alleyoop

[rcapete007]

what I don't understand is that it happened with the carb that was on the scooter but i put a brand new carb on and it did the same thing with the new one....... is it possible both have bad float adjustments or be blocked?

[Guitarman]

Three things come to mind right off...

1. Something was supposed to be connected on the first one and wasn't. Since you didn't see it on the first one, you didn't do it to the second.

2. It's not the carb at all, but look at where it mounts to the engine. Any gaps? Any dings, dents, bits missing that would allow gas to escape?

3. Is it the exhaust gas catcher thingie that is regulated by the EPA and which you should re-route so it works better? (A certain member here has diagrams of how to do this. It eliminates the strong gas smell you get all the time from some bikes.)

[Alleyoop]

Jul 6, 2014 20:03:54 GMT -6 rcapete007 said:

what I don't understand is that it happened with the carb that was on the scooter but i put a brand new carb on and it did the same thing with the new one....... is it possible both have bad float adjustments or be blocked?

When gas comes out of the OVERFLOW VENT TUBE, the problem is the gas is not being shut off when the float pushs the plunger to seal the fuel inlet "PERIOD". No other little THINGY or THANGY will cause the fuel to overfill the carb bowl. There is only ONE FUEL LINE from the PETCOCK or FUEL PUMP which ever one you have that FILLS the carb bowl and ONLY ONE THING that stops the fuel from coming in to the CARB BOWL.

Usually what makes them FLOOD is there is VARNISH build up in the FUEL INLET HOLE that the PLUNGER goes into to shut off the fuel from coming in and in that case fuel keeps coming in because the crap in the hole is not allowing the rubber plunger to seal the inlet. So it may not be the FLOAT itself it just may be crap buildup in the carbs fuel inlet also Crap builds up on the rubber part as well.

So yes you can have any number of carbs that will do weird things, DON'T forget you don't know how long that new carb was sitting on the shelf or wherever it was. Carbs do not fly off the shelfs they probably have carbs sitting on the shelfs for years and you don't know in what kind of environment either.

Take a picture of the Fuel Hose from the tank to the carb I would like to see how you have this setup.
Alleyoop

Here is how to post pictures.

scooterdoc.proboards.com/thread/10064/post-pictures

[Bashan]

Right on!

[3menim]

Jul 5, 2014 19:41:36 GMT -6 Alleyoop said:

OR from the Carb Drain which would normally have a hose on it and hanging down?
Alleyoop

[br

Hey I'm having the same problem where it is leaking gas from the drain tube that is just hanging there. I haven't tried to see if it leaks while running, but when I shut it off, I noticed it leaking quiet a bit. What should I do?

[cyborg]

Probably the float is either stuck down so the valve is not closing to shut off the gas or the tip of the valve is bad so it's not shutting off the fuel