hi Mercer it all depends! if your recoil starter is like the ones found on lawn Mowers then there must be some water or old oil freezing, also metals are stiffer when they are cold, I can prove this to you buy having you take an empty pop can and putting it in an oven for 20 minutes at 200 when you take it out a very simple squeeze will collapse it! and when cold it is harder to squeeze!
mercer, the grease inside the rewind is getting old and hard....you can try to get some WD40 into the spring, but if this doesnt help it will be a take apart, wash out and re-grease...
