I am doing a 599d eng fitted to an old Atco mower , main problem being the recoil the spring is not the strongest and after cleaning oiling and re-ass it i find it will turn the centre lock bolt i have tried removing the copper thrust washers adding a thin washer but nothing seems to work, the last time i worked on these was 45yrs ago and seem to remember they were a pain in the ar– then, any suggestions, i might add it was removed by owner because he had problems with it.