How full is your gas canister?

How warm is your gas canister?

I believe that in the cold temperatures at this time of year these are quite important. If you haven't done already, I would try taking a new can from inside the house (where it is warm) and giving it another go. If it starts fine then you know where the problem is.

I had a similar problem with my Jetcat before I learnt how much gas to use and it would start to ramp up on the gas and then stop (fuel ramp had not started sufficiently).

Just a guess though. I'm sure someone more experienced than me will be able to help more.