Fuel not shutting off (occasionally)

[David2021]

My 12 Tourer Solex 30FA1 ..LK61 occasionally suffers from the problem of the needle valve not shutting off the fuel. It is a 1.5 and the float is 26GR (?)
I have an SU pump (no idea which model/pressure).
The needle valve passes the suck /blow test!
Taking apart, cleaning, putting back to see what happens!
David

[David2021]

All cleaned & put back (plenty of red silt at the bottom of the bowl, but nothing to block a jet nor valve). However it still overflowed.
The leak appeared to come from the throttle spindle...the easiest route I imagine. I see there have been previous discussions about fuel height levels When i took the top off the float looked pretty high so should have operated the valve. Is the SU pump forcing fuel past the valve? What path does the overflowing fuel take?
i HOPED WHEN i GOT OUT ODF AUSTIN SEVENS THAT i HAD SEEN THE LAST OF RAW FUEL POURING ONTO HOT MANIFOLDS.....
Still at least it doesn't overflow when driving along.... I don't think so anyway!
Oh the needle valve has a single fibre washer.
David

[luli]

The fuel level in the float chamber is a balance between three factors: The input fuel pressure, the height of the needle valve and the weight of the float itself.
You must use a low pressure fuel pump like SU AUA25, with typical pressure of 1.5 psi. The height of the needle valve should be adjusted by selecting the correct shim between it and the carburetor cover. The nominal float weight is 26 gr but 23 are available and will help in difficult cases.
Read more here: https://wp.me/pXLKy-29V

[David2021]

Everything looked ok & it seems to have cured itself! So, if it ain't broke....