A couple months ago I upgraded my standby generator to an electric start because my old pull start was getting too difficult for me to start. A few days ago before it got bitterly cold, I pushed the button and it fired right up. But the night before last when it got down to well below zero, I tried to fire it up again. It started, but it took some doing! I know the battery was charged, but it was so cold that it labored to crank and it took me a few attempts to get it running. Here's what I did.
Yesterday afternoon I went down to Harbor Freight and they have 72x80 quilted "moving blankets" on sale for $6.99. I picked up three of them because that's a great price and they could be useful for other things. Besides, my neighbor has an electric start generator too and I know that he will want to try this too. I came home and put a drop light down on the floor right next to the engine block of the generator. I then covered the whole generator with the blanket. It was the perfect size and covered the whole thing and just touched the ground all the way around and it made a nice tent for it. This was at about 6:00 last night. I just went out there about a half hour ago and uncovered it. I put my hand on the engine and it was pretty warm. I closed the choke and hit the button and the generator was running in about a second and a half! This was a very cheap and easy way to fight off the effects of the bitter cold.
Even if you don't have an electric start generator, this will probably help greatly if you have a pull start. It keeps the oil much warmer and makes it easier to start. I'm not sure, but it probably doesn't cost much more than fifty cents to run that 75W bulb for a whole day. This is something that you'll only need to do when it's bitter cold, but it's easy to do and can save you a lot of headaches if your power does go out during a winter storm.
I hope this helps!