Paul, That particular configuration has a bit of a safety issue. You always want at least one of your pumps before the gascolator. Check out any low wing carburated Piper. The fuel flow goes from Fuel Tank -> Electric Fuel Pump -> Gascolator -> Mechanical Fuel Pump -> Carb.
The reason why you want one fuel pump before the gascolator is that even the smallest leak in the gascolator will draw air under suction from the pumps and starve the engine for fuel. If you have a pump before the gascolator, you can turn on that pump to restore fuel flow. You may only have a small seep or drip at the gascolator under pressure, but that's enough of an air leak under suction to starve the engine. This was a really common problem with the GlassAir series of aircraft. They were designed with the gascolator under suction for the mechanical pump and had chronic problems with fuel starvation thanks to an O-ring seal that didn't seat well in their gascolator. Ideally, the first pump should not have to suck fuel up hill, which eliminates the same problem should there be an air seep at a fuel line junction between the tank and the pump. But the gascolator can be a real problem because it is disassembled and reassembled regularly, so it's easy to have an air seep on occasion. -Jeff Scott Los Alamos, NM ? Here is a picture of my first layout of my duel facet fuel pump design. ?I got it from flycorvair.com. ?I ended up with something diferant with the same pumps. https://flic.kr/p/AoAMfe Paul Visk?Belleville IL ?618 406 4705 Sent on the new Sprint Network from my Samsung Galaxy S?4 ?
