1970 Johnson 1.5 HP Outboard Motor 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 10ss of needles in upper main bearing Install oil seal, lip down until f1ush with top of crankcasePISTON INST ALLATION 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 placed toward the intake portSee Figure 5-18
Figure 5-19Correct Piston Installation
PISTON RINGS Install the piston rings pistonSpread each ring with ring expander just enough to slip it over the head of the piston and down into See Figure 5-20sure 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 the edges of the ports in the cylinders, but to assure staggering of the ring gapsCarefully install piston and rings into cylinder boreDamaged piston and broken piston rings result from imperfect a1ignment of the ring groove and the piston dowel pinsRemove connecting rod ROD