1971 Evinrude Mate 2HP outboards Service Manual, Page 37Get this manual
5-7 UPPER MAIN BEARING AND OIL SEAL Install upper main bearing through bottom of crankcasePress against lettered side of bearing case until bearing is recessed 116" below finish thrust face of crankcaseAvoid loss of needles in upper main bearing Install oil seal, lip down until flush with top of crankcasePISTON INSTALLATION Coat piston and cylinder bore with oil and install piston and connecting rod assembly through front of crankcasePush piston through cylinder until piston ring grooves are exposedThe intake side of the piston deflector must be placed toward the intake portSee Figure 5-1868 1054
Figure 5-19Correct Piston Installation
PISTON RINGS Install the piston rings on pistonSpread each ring with ring expander just enough to slip it over the head of the piston and down into placeSee Figure 5-20Be sure the rings fit freely in the piston ring groovesThe ring grooves are pinned to secure the position of the rings, primarily to prevent ends of the rings from catching on the edges of the ports in the cylinders, but also to assure staggering of the ring gapsCarefully install piston and rings into cylinder boreDamaged piston and broken piston rings may result from imperfect alignment of the ring groove and the piston dowel pinsRemove connecting rod capCONNECTING ROD aIf removed, replace needle bearing liners in connecting rod and cap