200 tdi boost pin and pump adjustment

Cheers from across the pond. I have a 1993 Range Rover Classic 200tdi that I recently imported from Spain. The engine is healthy and recently had a full rebuild <2000 miles ago. I just installed a boost pin and was getting a lot of black smoke at full throttle so I wound down the main power screw on the back of the pump by a full turn (counterclockwise). A couple of questions.

1. I did not remove the metal locking collar on the screw, but instead loosened the nut so it would turn freely. Is that ok?
2. Does turning the main power screw effect idle? I think my idle dropped below 500 and is very low upon startup.
3. How much black smoke is ok. I am getting a little black smoke at full acceleration, but power is nowhere near it was before adjusting the screw.
4. Going to install an uprated intercooler. Will I have to re-tweak the fueling after I install it?

Thanks

have a read of these.

Cheers

Put it back to std ie remove the eew boost pin, then rotate diaphragm with std pin and power screw 1/4 turn clockwise.
Very difficult to make power on the old engines without smoke.

Yes winding power screw out to far will effect idle, go to far and you also lose power, quite a lot.

Has anyone just replaced the fueling pin for more low end boost with out any other modifications. Would like to know the results. My injector pump is new but engine has approx 300 000kms. Runs great just like to keep up with traffic!