A kit for the cylinder-piston group: a piston 40 mm in diameter, a 10 mm pin and a ring. Fits Oleo-Mac 941/942 and EFCO 141/142 chainsaws. Country of origin: China.
The piston needs to be replaced if there is scoring, cracks, a burnt-through crown, worn ring grooves, or excessive clearance in the cylinder. Signs: loss of power, smoky exhaust, hard starting.
