Answer: There is no difference to the valves except that the FS20x4 has a detent in the middle position for BOTH, whereas the FS20-3 has no detent. It is Not recommended that the FS20x3 is used in the centre position as vibration could cause the valve to move round to the position in between LEFT and BOTH and here there is a restriction in the fuel supply.
Answer: A Gascolator is a device for tanking the water from the fuel. The Andair Gascolator uses gravity coupled with a PTFE coated 70 micron screen to ensure no water makes it into the engine.
Answer: Yes. All of the Andair products have been designed to be used for high pressure fuel systems. When the GAS375 was pressure tested it could hold 1000psi with ease. The unit then ruptured at 1700psi.