RE: Welcome to Club SAITO !
Jett:
Sounds like it's time for a different trick.
Run the pressure screw back in to about a 1/16" gap, and run the vent hose out the tail of the plane. This is going to put the pressure 'way up, that's why there's a second part to the trick.Now put a tee in the feed line from the pump to the carb, as close to the carb as you can get it. Connect a return line to the tank from the leg of the tee. You'll still need a tank vent - three lines now to the tank.
Adjust the carb as though it was running normal muffler pressure.
An alternate, if you would like to try it, is replace the hard hose supplied with the pump, just use normal silicone hose. This will lower the pressure a bit.
Bill.