.010 Oversize Piston Kit for Kohler K301 M12 12HP 47-874-08-S

Piston kit .010 inch oversize for Kohler K301 12HP and old style M12 engines, replacing Kohler part number 47-874-08-S. The kit contains the piston, the ring set, the wrist pin and the clips. Standard bore on the K301 is 3.375 inch, 85.73mm, so a cylinder bored .010 oversize finishes at 3.385 inch, 85.98mm. This kit is intended for an engine whose cylinder has already been machined oversize, not for a standard bore. Measure the finished bore before ordering, since a block taken to .020 or .030 requires a different kit. Kohler divides the K301 piston into early and late families that are not interchangeable. This part covers engines built before serial number 1730100013, while later blocks use 47-874-18-S. Check the serial number on the engine tag. The K301 is a single cylinder engine, so one kit completes it. Hone the cylinder before assembly and stagger the ring end gaps around the piston.

• FITS KOHLER K301 12HP AND OLD STYLE M12 engines whose cylinder has been bored .010 inch oversize. Replaces Kohler 47-874-08-S. In the kit: the piston, the ring set, the wrist pin and the clips. Standard bore on a K301 is 3.375 inch, 85.73mm, so a .010 oversize cylinder finishes at 3.385 inch, 85.98mm. This kit is for an engine that has already been to the machine shop.
• MEASURE THE BORE FIRST. This is not a kit you order on guesswork. If the block is still standard, this piston will not go in. If it has been taken to .020 or .030, this one will be loose and the engine will smoke and slap. Put a bore gauge in it, or ask the shop that did the work what they finished it at.
• EARLY ENGINES ONLY, AND THIS MATTERS. Kohler split the K301 piston into two families that do not interchange. This part covers blocks built before serial number 1730100013. Later engines use 47-874-18-S, a different piston design. Check the serial number on the engine tag before ordering, because the two pistons look similar and are not the same part.
• ONE CYLINDER ENGINE, ONE KIT. The K301 is a single cylinder, so one kit does the whole engine. No second order needed.
• DO THE JOB ONCE. Hone the cylinder to give the rings a crosshatch to bed into, check the rod and the crank journal while you are in there, and fit a new head gasket and breather gasket. Set the ring end gaps to your engine manual with the ring squared in the bore, and stagger the gaps around the piston on assembly.