Hello, We have an old Hayter Osprey 24" rough cut mower. Serial No. 13957. (It's dark green if that helps). With a 7HP Briggs & Stratton pull start petrol engine. Do you have a user manual for this model? I have found a manual similar but not quite the same as ours has a slightly different set up at the handle bar (two hand levers, not one engine stop lever). This is the part we are having problems with. Thank you. Jane