Vacuum control adjustment
 

What is the drill for ajusting the vacuum control (on the fuel pump)
I have 15" but 4"- 5" at fulll throttle and a 2 - 3 flare.
I understand the vacuum at full throttle should drop to 0" or very close to it. The orifus is in place on the black supply "t" on the brake booster line. the car is a 1985 300 D turbo.
Will the control have to be removed to adjust and which way is the stem turned to dump nore vacuum.
Thanks, John