Just remembered, a test you can do to check the pump. Remove pump and install a piece of aluminum can over pressure port at the oring on rearend housing and remove the plug from the pump casting and hook to flow rater. Make sure flow rater is open when you start engine. Should be 15 gal. Per minute. as you stated.Slowing turn down flow to higher pressures and watch flow, but don't turn off tight as you could destroy pump