• Onan manufactures the P220G engine for use in lawn mowers and other machines requiring small engines.tractor image by Alison Bowden from Fotolia.com
  
  Onan manufacturers the P220G engine for use in machines such as lawn and garden tractors and front mowers. When the engine used in a lawn and garden tractor, engine has the machine number 420; when used in a front mower, it carries the machine number F910.
  
  

Specifications

• The Onan P220G engine uses a two-cylinder, four-stroke design. It has a total piston displacement of 782 cubic centimeters, or 48 cubic inches. and a total power output of 20 horsepower. The engine has a bore (cylinder diameter) of 82.55 mm (3.25 inches) and a stroke (piston traveling distance) of 73 mm (2.87 inches). The piston pin bore ranges from .6877 and .6881 inches. The oil pressure regulating valve has a length of .5 inches at 2.6 lbs. of force.
  
  

Torque Specifications

• The engine has a connecting rod cap nut has a torque of about 159 +- 9 inch-lbs.. The exhaust pip cap screw has a torque of 97 +- 27 lb-in. The intake manifold attaching cap screw has a torque of 53 inch-lbs. The gear housing cap screw has a torque of 88 inch-lbs., while the oil pump to cylinder has a torque of 97 +- 9 inch-lbs. The flywheel cap screw has a torque between 50 and 55 foot-lbs. The cylinder head attaching cap screw has a torque of 180 +- inch-lbs.
  
  

Dimensions

• The engine's carburetor float level has a 1 mm height from the edge of the bowl, while the carburetor float drop has a 5 mm depth below the edge of the bowl. The breaker point gap opening measures .41 mm. The engine has a governor cup travel of 5.6 mm, a intake lobe height of 29.7 mm and an exhaust lobe height of 29.5 mm. Camshaft clearance ranges from .038 to .076 mm, and total piston-to bore-clearance ranges from .076 to .127 mm. The piston pin bore measures between .6877 and .6881 inches, while the rod-to-crankshaft bearing clearance measures .051 to .084 mm. The crankshaft bore I.D. measures 41.35 to 41.36 mm, and the engine has a bearing clearance ranging from .061 to .097 mm.