1980 Johnson 4HP Service Manual, Page 57Get this manual
kIf necessary to remove pistons from connecting rod, remove wrist pin retaining rings, using Special No325937See Figure 5-9Drive wrist pin through to free piston from necting rodSee Figure 5-10 .1m NOTE
side piston is marked "L" insideWhen wrist pin is to moved, "Lside piston must down and driving too must appied not to distort to tight endpistonSee Figure 5-11
Figure 5-11"L" Mark
CLEANING, INSPECTION, AND REPAIR
CYLINDER BLOCK AND CRANKCASE Check cylinder walls for excessive wear and accumulationcheck cylinder ports for Cylinder walls wear in various degrees dependlubrication and conditions under which ing the motor is operated Major portion of wear is in the port and the covered ring travelCheck cylinder for size and wall straightness using inside micrometer dial indicatorRefer to Section for specified dimensionsIf wear is greater than 0.002" (0 .05 replace cylinder bIock bIock for overavailabIe size pistonsPiston and ring sets oversize0.030" (0.76