1972 Johnson 2HP 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 1ettered side of bearing case until bearing is recessed 116" be10w finish thrust face of crankcaseAvoid 10ss of need1es in upper main bearingB NOTE
Install oil sea1, lip down until flush 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 p1aced toward the intake portSee Figure 5-18
Figure 5-19Correct Piston Installation
PISTON RINGS Instal1 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 free1y in the piston ring groovesThe ring grooves are pinned to secure the position the rings, primarily to prevent ends of the rings from catching the edges of the ports in the cylinders, but a1so to assure staggering of the ring gapsCarefully install piston and rings into cylinder boreDamaged piston and broken piston rings result from imperfect alignment of the ring groove and the piston dowe1 pinsRemove connecting rod ROD