I had the same problem last night with my plane (Evo .40 engine)...wouldn't start very easy. finally got the thing running, but it wouldn't stay running. Messed with the high & low needles without much success. We had it running good on the stand, but as soon as we tipped the nose up in the air it died.

Spent an hour messing with it tonight (20 degrees warmer), and it runs like a champ.

So I'll echo bodypilot's thoughts: Any other suggestions on how to get them started in the cold?