Originally Posted by
drac1
So it's a pressurised fuel system, which explains why the engine doesn't go lean as the fuel level drops.
No more pressure than a regular tank. It just puts the pressure where it is needed. At the clunk/fuel pickup. In many CL models, the tanks just use the ram air into the Uniflow vent. Many of these engines did not use mufflers. Ram air, or muffler pressure will work.