nrad2000

I have an OS FS 91SII w/ pump. Would there be a problem with engine performance if I run exhaust pressure back into the tank?

bigtim

My Feedback: (13)

don't do that, its what the pump is for, a pumped 4stroke shouldn't have a pressure nipple installed on the pipe any way.

the tank should be vented so there is no positive pressure.

one line for supply
one line to fill
and a vent line with the brass pipe in the tank towards the top of the tank so air can get in and the fuel can be drawn out by the pump.
the vent line can be routed several ways a couple loops around the tank and then exit out the hole in the front of the fuse and down, or a length that just goes up above the top of the tank then out the bottom of the fuse, when the engine is running the fuel wont exit out of the vent line because of the neg pressure from the pump only air in.

it really doesn't matter how long the air vent line is within reason, it serves a dual purpose as a overflow fill the tank until it comes out the vent and catch the excess in a container