I can't believe how many subtle twists and incantations there are to coax individual engines into life. But I wish I could find one that worked on the particular O320 in my Pup. I have to allow at least half an hour to get her going in the winter. Cranking, letting the fuel drip out and the starter cool, cranking, dripping , cranking, go for a walk for 15 minutes, repeat. She goes in the end, but twice I've had the nosewheel on fire on the way there. And before anyone says I'm over-priming, I tried without ANY strokes last time, just to see what happened, and after two 10 second cranks there was still fuel dripping out of the carb.
The engineers (claim to) start her first time every time, but their described method doesn't work for me. Four pumps, throttle open a crack and both mags (in spite of the book saying one). Not even a hint of a cough when I try this. And of course you can't really practice because once she's started once there is no difficulty with subsequent restarts.
It's got to the point where I'm put off even trying in winter. So she sits in the hangar for three months.