1975 Evinrude 2HP Model 2502 Full Factory Service Manual, Page 38Get this manual
5-6 ring landsSee Figure 5-13Check piston for size and roundness,
using micrometerCorrect sizes are given in Section 2
Before insWling new piston rings, check gap between ends of ring by
placing ring in cylinder bor e, then pushing ring down in the bore slightly with the bottom of the piston to square it upSee Figure 5-14Check
for ring groove clearance with feeler gageSee Figure 5-15Correct
gap and groove clearances are given in Section 2
REA SSEMBLY OF POWER HEAD
for, and mak no "dry" ass mbliesBe ure all parts to be assembled
Proceed lowlyMake no forced assemblies unless press fits are called
Figure 5-13Cleaning Piston
Ring Groove
are clean and free from dirt and gritA perfectly good cylinder wall, piston, and rings can be ruined in few minutes of operation unless all