OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Four Stroke Lawn Mower Frames Atco 4S20

The peterm picture was a 1950s ATCO. The diagram below (Fig 9 from the manual) is a later (handlebar) ATCO. It may be more like yours - but the differences are not all that great anyway (chain tensioner, clutch on one sprocket, etc.)