To fuel my CAP 232, I have a third (fill) line in my fuel tank. I put a "T" connector in the pressure line. Both these lines have a plug. To fuel, I make sure the throttle is completely closed, and connect the fuel fill line from the pump to the fuel fill line to the plane. I connect the fuel pressure line back to my fuel bottle vent. When the tank is full, the overflow from the pressure (vent) line drains out the overflow back to the fuel bottle. There is usually some that goes to the muffler, but the engine is mounted sideways (muffler down), so there is no risk of flooding the engine from the overflow. I have found that if I'm careful, and leave the throttle partially open, the pressure from filling the tank will also prime the engine.

I have tried using a hemostat to pinch the pressure line from the muffler to prevent fuel flow out the muffler, but have had mixed results (torn fuel line, hemostat slips off, etc).

Also, make sure you have sufficient airflow through the cowl by ensuring the exit hole area is larger than the inlet holes at the front.

Good Luck!
Brad