1977 Johnson 2HP Outboards Service Manual, Page 40Get this manual
5-6 ring landsSee Figure 5-13Check piston for size and using micrometerCorrect sizes given in Section 2Before installing new piston rings, check gap between ends of ring placing ring in cy1inder then pushing ring down in the s1ightly 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 unless pressfits called for, and make "dry" assembliessure parts to assembled clean and free from dirt and gritperfectly good cy1inder wall, piston, and rings ruined in few minutes of operation forms of grit removed before assemblyWork in clean ings and with reasonably clean handsCoat bearing surfaces, cylinder wall, etc with clean before assemblyWhere the use of is specified, we recommend Outboard Lubricant
Figure 5-13Cleaning Piston Ring Groove
Always use new gaskets coated lightly with gasket sealing compound part 317201 when reassembling the power headPISTON, WRIST PIN, AND CONNECTING ROD The relative position of piston and connecting rod must considered in reassemblyPiston must installed rod as illustrated in Figure 5-16Apply coat of to wrist pin, making sure surface is cleanPlace drop two of in wrist pin holes in the pistonInsert wrist pin through slip fit side of pistonwrist pin bearing in connecting rodPlace connecting rod in position, then proceed to install the wrist pinThis accomplished easily if the piston is heated s1ightly, causing it to expand