non starter

[tbone]

The valve is tapered and simply gets pushed up into its hole by the float to stop the fuel entering the bowl.
The valve can wear and allow fuel to pass even when fully seated but i`d be more inclined to look at the float first.

[gpz]

TB ive looked at the float its plastic  dont know if they all r  but it looks ok no fuel in it so dont know what else to look at

[tbone]

Yep, hard plastic. Is it moving freely, when you push it up is it fully seating the valve?

[gpz]

yep seems to be moving up and down freely

[tbone]

And seating the valve? you can check by removing the top of the bowl and attaching your gravity fed supply, holing the float `up` should cut off the supply.