Squirt the lighter fluid (couple of drops) into the intake, then hit it with the starter. The lighter fluid aids in starting because it will flash off faster. It also has no oil to slow things down. If you can get a propane torch, you can use it to heat the engine as well (very carefully though). Generaly here, the electric starter will do the job as it rarely stays below 5deg C for any length of time. Let them warm up for a minute or two before you run them up. A needle adjustment maybe in order as well.