This replacement lower crankshaft oil seal is intended for fitting on robust Briggs & Stratton petrol engines of 10 HP and 12 HP. As the key sealing element on the lower part of the engine block (where the crankshaft exits towards the mower deck or driveshaft), this oil seal has the primary role of preventing engine oil from leaking along the rotating shaft and ensures constant lubrication pressure inside the crankcase. Besides retaining the lubricant, it hermetically protects the inside of the engine from the ingress of fine dust, cut grass, soil and moisture from the terrain, which would otherwise quickly contaminate the oil and cause accelerated wear of the bearings and crankshaft. When servicing and replacing an old, hardened or cracked oil seal, it is necessary to completely and carefully clean the seat in the engine block and the surface of the crankshaft itself of residue of old sealing material, rust and dirt deposits. Any groove or damage at the point where the seal sits can cause premature failure of the new seal. Before pressing it in, lightly coat the inner sealing lip of the oil seal with clean engine oil so that it slides more easily onto the crankshaft and is not damaged during the first "dry" start of the engine. Press the oil seal in evenly and perpendicular to the shaft, using a dedicated tool or a suitable driver that will not deform the outer housing of the seal. Key characteristics Part type: Crankshaft oil seal (lower) Manufacturer: high-compatibility aftermarket part Material: Highly resistant rubber (NBR/Viton) with a steel spring ring Inner diameter: Ø34.9 mm (nominally 35 mm) Outer diameter: Ø47.6 mm Width (thickness): 8 mm Original catalogue number (OEM): 291675 Compatible models Four-stroke petrol engines: Briggs & Stratton tractor and stationary engines of 10 HP and 12 HP that use the stated factory part number.