The mag deck mowers from the 60s and 70s would be some of the lightest ever made. Especially the 18 and 19 inch models. I have a mag deck 19 inch 1964 model 5232 and a 1977 model 5024, both are the lightest that I've ever used. If you are looking for a newer model 2 stroke I think there are a few F series 19 mowers that are super light as well. The models 10400 and 10401 are really light weight pushers. Almost all of these old 2 stroke Lawnboys are so light that self-propel is really unnecessary in my humble opinion.