1972 Johnson 2HP Outboard Motor Service Manual, Page 36Get this manual
5-6 ring landsSee Figure 5-13Check piston for size and roundness, using micrometerCorrect sizes are given in Section 2Before instal1ing new piston rings, check gap between ends of ring placing ring in cylinder bore, then pushing ring down in the bore slightly with the bottom of the piston to square it See Figure 5-14Check for ring groove clearance with feeler gageSee Figure 5-15Correct gap and groove clearances are given in Section 2 REASSEMBLY OF POWER HEAD
Proceed slowlyMake forced assemblies un1ess press fits are cal1ed for, and make "dry" assembliessure parts to assembled are clean and free from dirt and gritperfectly good cylinder waH, piston, and rings ruined in few minutes of operation unless forms of grit are removed before assemblyWork in clean surroundings and with reasonably clean handsCoat bearing surfaces, cylinder wal1, etc with clean before assemblyIIIIINOTE Always use new gaskets coated with gasket sealing pound part number 317201 when reassembling the power headPISTON, WRIST PIN, AND ROD
Figure 5-13Cleaning Piston Ring Groove