Here is the response when I e-,ail GPI recently on the pump gears swelling.
"There have been a change in the formulation of the gears in the past couple years.
I would suggest that fuel setting for long periods of time may cause some of the issues you speak about (gasoline goes through many changes when stored)."
You can contact the factory for more information at:
Great Plains Industries, Inc.
5252 East 36th Street North
Wichita, KS 67220-3205
Phone:316-686-7361 / 1-800-835-0113
Fax:316-686-6746
E-Mail:pumps@gplains.com