Most people could not figure out how to set the pump pressure "back in the day". Mostly, this was a result of not reading the directions.

Here's how you do it: Set you high end needle, and idle. (If the high end needle is way off, adjust the pump accordingly.)

Then- the "magic" part- bring the throttle to mid range, and adjust the pump to the correct mixture. The pump is largely responsible for the mid-range mixture. Give the high and low speed needles a final tweak, you are done. Go fly!

You may need to go through more than one iteration of the above procedure to get it perfect. Once it is dialed, it is set-and-forget. It was (and probably still is) a great fuel system.

-Robert