You have a couple different things that are making it hard to start. Often a bit of fule gets into the cylinder making it hard to start. Also sometimes it could be oil residue left over from a previous flight draining into the cyliner from the crank case or muffler. To get rid of this pull the plug and spin the motor over. The second thing is the temperature, sometimes the motors don't want to start as easily as on a warm day. Many people keep the helo in a warm car until they are ready to fly. Also since the mixture has to be richer on cold days there is a better chance of flooding and hard starting. It is acceptable to loosen the plug so you can get the starter to turn the motor over and then once started tighten the plug before you fly.