Peter,
you might have the wrong pump lever fitted.
The two original pumps I have are fitted with levers of casting number "1524280"
The Standard Vanguard pump I have uses 1524043 which is quite different .
I've attached a photo of the pump lever and sketch which shows the angle between the working surface on the cam and the machined surface between the locating tit of the spring and the pivot point hole of the lever is approx. 60 degrees .
http://www.bristolcars.info/forums/a...1&d=1397080785
If you have the wrong lever I doubt that it will work except at idle .
Geoff