Personally I have never had much success running the pump. Two methods I use:
1. Idle engine then stop using the mags (turn off key). Do not touch mixture, leave rich. Then, no prime, start like car, use high prime to keep running. Great for stop/start
2. Use half of normal cold prime then crank while opening throttle. Most will start somewhere around 3/4 open. Pull back throttle, use pump to keep running. Great for a 15 minute stop.