RE: Single or Multiple Fuel Pumps?
I use 3 or 4 different fuel mixes for my different engines and I use just one pump. I just switch the jug on my field box. I have a Hobbico field box and electric pump and all I do is reverse the pump to empty the lines of fuel back to the jug and switch jugs. However, I don't think it would be necessary to void the lines of one fuel to switch to another as the small amount of fuel in the lines won't change the nitro/oil content of the new fuel being pumped by anything really measurable unless your fill line from the pump is 6 feet long.