Here is a basic rundown of what you can easily do at home with a dremel, a small tip and some 100 grit sandpaper to better your performance and get a basic blueprinting job on your pump.
Blueprinting is the process of making a part as perfect to it's engineering dimentions as possible, removing any manufacturing flaws or deviances such as casting marks, seams, misalignments, etc. Often when doing parts such as a pump, a bit of modification is also performed such as smoothing down rough edges or removing small amounts of material to better the water flow, even though they were actually designed that way.
NOTE: removing material from your pump can result in a weaker structure and can make it more prone to stress fractures or failures.
Here are pictures of what material you want to remove and smooth out. You want all these seams and surfaces to be smooth.
You want the edges of the vanes, on both sides, to be smooth and rounded. Any knicks must be filed down, the edges should be straight across the vane with a tip like an airplane wing, nice and smooth. Your impeller, however (if stainless steel and not aluminum like older skis) needs a very sharp straight edge. File the edge sharp, but only angle the inside surace (the edge pushing the water). The outer surface should remain flat with the blade.
[ May 07, 2003, 10:37 AM: Message edited by: Technical Support ]