fuel feed system,O.S.91SII???

Normally, there is a line running from a pressure fitting nipple on the muffler to the vent of the fuel tank. This provides a slight positive pressure that helps the engine draw fuel. Dr.1 Driver "There's a Hun in the sun!"

Should I used two vents, the fuel tank allows for 2; or just the one from the muffler????

It depends, Ken. If you can get to the supply line easily to pull it off and refuel, then you don't need an extra line. If you can't, then you will need an extra line to fuel and defuel. Only one vent line is required; from the muffler to the top of the tank.

Dr.1 Driver "There's a Hun in the sun!"

Of course, if you use an extra line to fill the tank, it must be plugged after filling. A pressurized system doesn't really have a vent at all. What was the vent becomes the pressure inlet.

Jim - AMA 501383

Dr1Driver wrote:

I'm going to use a Great Planes Easy Fueler Filling valve mounted in the fuselage on the pressure line between carb and tank for fueling and emptying...ken

I have found that fuel filler to be unreliable when used that way. After a while, it tends to restrict flow when not being used for filling. I do use them strictly for filling the tank. But when I do, I also have a vent line which I plug after filling. Fuel dots appear to be the current favorite for use in filling a tank. Just run a pluggable line to a second filler which extends to the back and bottom of the tank.

Jim - AMA 501383

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