Interesting..... I did observe that when the pump is turned by hand, with the upper screw completely removed, some oil came out. Looking at the exploded view more closely, the ballast assembly seems to be mounted to the lower hole. But the upper screw plugs a drilled passage which connects to the second stage on the intake side of the pump chamber. Need to check a bit more.
Dave Cooper
Created on Monday, April 09, 2001 8:28 PM EDT by David Cooper