Hi Jack and Greg,
This is the HD model that appeared in about 1963. They are slightly lighter than the previous model. The previous version of the mower had a Mk12 Villiers 4 stroke engine with kick starter which was replaced on this model with the lightweight 150cc Villiers 4 stroke engine with a recoil starter. Having a look at the starter that has been attached to this one, it is most certainly interesting but it is not original as Atco abandoned the crank start prior to WW2. These mowers came in a 20" and 24" variant as well as a 20" Special which had different front rollers and rear transport wheels fitted.
Kind regards,
Sir Chook
