1978 Johnson 55 HP Outboards Service Manual, Page 68Get this manual
Before installing new piston rings, check gap between ends of ring by placing ring in its respective cylinder bore, then pushing the ring down in the bore slightly with the bottom of the piston to square it upSee Figure 5-29Check lower ring for evidence of tightness or binding by rolling the ring around the piston ring grooveSee Figure 5-30Check for groove side clearance with feeler gageSee Figure 5-31Correct gap and side clearances are given in Section 2 LOWER RING LAND ONLY