Abstract: A crankshaft impact protector for protecting the crankshaft of a lawnmower engine from bending beyond its elastic limit whenever a hard or immovable object like a rock or a stump is struck by the lawnmower blade. The protector has a flange for mounting on a mower deck, a mounting base for mounting the lawnmower engine thereupon and a bumper for providing physical support to the crankshaft. Impact forces experienced by the crankshaft are dissipated by the bumper of the protector and shifting of the bumper with respect to the crankshaft is prevented because the engine is integral with the crankshaft impact protector. A small clearance is provided between the bumper and the crankshaft thereby also helping to prevent soil and dust from traveling therethrough and reaching the main bearing of the engine.

Abstract: A connecting rod for reciprocating piston machines having piston pin and crankshaft ring portions with bores therein connected together by a load bearing member. The load bearing member has voids within it adjoining the outer perimeters of the piston pin and crankshaft ring portions. When press-fitting a liner or cup bearing within the ring portion bores, the voids allow the piston pin and crankshaft ring portions to expand radially uniformly at the connection between the ring portions and the load bearing member such that the liner and bearing retain a substantially circular shape.

Abstract: A two cycle crankcase scavenged internal combustion engine having an exhaust gas recirculation system. Exhaust gas from the coolest part of the exhaust muffler is recirculated back to the crankcase in a controlled discrete charge on each cycle of the engine. A recirculation port extends through the cylinder sidewall and is opened briefly during the compression stroke of the piston to thereby enhance vaporization of the fuel and increase velocity of the scavenging air-fuel mixture into the combustion chamber.