I've had it ultrasonically cleaned and fitted new float and float needle. I can see that the needle seats correctly when the float rises. There's no sign of the float catching on the walls of the float chamber and it moves freely on the pivot, so I'm at a loss at the moment, mate.
I thought the ultrasonic cleaning had worked at first. It seemed to.
Anyway, I'll have one last fettle, and if that doesn't work, I'll order a new Dellorto/Spaco SI 24/24.
Thanks for your help again, mate
