New engine trouble.

The next time it starts to sputter, loosen the gas cap. I bet your cap is not venting properly.
Cold weather will affect how easily the engine starts but should not cause the engine to stall.
As for checking the spark plug gap, use a spark plug gapping tool, sold at most auto parts stores.

Also check for kinks in any vent tubing on the carb.

2 stroke engine problem,...
(sorry to piggy back on this thread, but I still can not start a thread for some reason)

My brother (a true dumb ass) ran my 2 stroke snow blower I had at my Mom's house with regular gas
(he "grabbed the wrong can" not the one marked "MIXED FUEL FOR SNOW BLOWER")
when he started having trouble with it running bad and not being able to start it with out the electric starter (it used to pull start real easy) he called me, after some phone interrogating we figured it out, I told him to,
1st, to KICK HIS OWN ASS so I won't have to and then bring me the thing without touching it again,...
I can get it started with the electric, it does run and idle,... but it doesn't sound like it used to and it won't pull start,....
any thoughts on how bad it's damaged or what happened in there,...?
or what if anything I can do,...?

Extreme accelerated wear is what happened to the poor snow blower engine.
It is toast.
As a band-aid effort for the remainder of the winter, I can only suggest running the proper fuel as you all ready know, and get it re-ringed with possibly a new piston ASAP. If you are lucky the cylinder hasn't been FUBAR'd too.
The crank and connecting rod bearings should be ok, but don't expect them to last as long as they would have before.

Your brother owes you a brand new engine.