This technical manual (tm-1235) is a service guide for the engines used in john deere walk behind rotary mowers. Included in the manual are specifications, diagnosis and adjustments, illustrations of special assembly and disassembly procedures. Applications: LAV 30 and 35 tecumseh engines used in the 19 and 21 mower, 92508 92908 110988 110985 briggs & stratton engines used in the 18 20 21 walk behind mowers. This manual is loose leaf and secured in a black john deere binder.