Saving Old Seagulls

Question - Why does the gravity fed Osprey need a throttle valve stop adjuster screw? Why do the silver century / late 40 model amal carbs not use this and is the 416 / 1 otherwise identical and can the body be drilled and tapped to take one? (I have a 416/ 1A which looked bonny on the outside but inside the bowl was very badly corroded).

The Osprey has a stop button to cut the motor, so has a screw to set tickover, so that it doesn't stall during use.

You could manage without this ability, try and see, use the osprey main jet.