Does anyone know what 1 and 3 should be set to from cold? What is the factory set position for them? Its the idle screws on a Pierburg 2E3. I have two Pierburg 2E3's and the position of 1 and 3 screws on each carb i have is different. So i recently bought another Pierburg 2E3 but a later one and my van runs much better now but the idle is fast and when i and try to slow it down the screw 1 does nothing apart from speed things up if i turn it clockwise but nothing if turn it anticlockwise it doesn't slow down as the screw is as far out as it goes and does nothing to slow down the engine, so i want to set screw one and three to the factory position before i put the carb back.
In the picture
2 is the fast idle cam
3 is the fast idle position screw
This cam is governed by the choke bi metal spring, and set by the corresponding springs.
It is 'set' by depressing the acc pedal before cranking the engine.
The screw is to adjust the position of the butterfly valve when the engine is cold.
A cold engine will need both choke and a higher idle speed
The top step on the cam is equivilant to 2000 rpm
With increments down to 900 rpm
The idle speed screw (1) is then in operation on a warm engine.
There are no "settings" only that screw no.3 is off the cam when the engine is warmed up.
As for screw no.1 that should be used to set the rpm to 900 at idle ui g a tachometer.