1972 Evinrude StarFlire 125 HP Outboards Service Manual, PN 4822, Page 56Get this manual
(3) Worn, galled, or abraded surfaceThese may be caused by two loose fit, or bearing locked by dirt and turning on shaft or in housing(4) Badly discolored balls, rollers, and racesThis is usually due to an inadequate supply of lubricantModerate discoloration of balls and raceways is not cause for discardSEALS aReplace upper crankcase head sealDO NOT reuse sealSeat new seal with lip facing in and flush to 164 above top of crankcase headbLower crankcase head seal should be replaced using seal installer (Special Tool #315768)See Figure 5-38PISTONS Check the pistons for roundness, excessive skirt wear, and scoringThe piston skirts must be perfectly round and unscratched to prevent the entry of exhaust gases into the compression chamberSee Figure 5-24Carefully remove carbon deposits from outside and inside piston head with care, do not round off deflectorInspect the ring grooves for carbon accumulation, excessive wear, or damage to the ring seatsCarefully scrape carbon from the ring grooves, making certain that carbon clinging to the bottom and sides of the grooves has been thoroughly removed without scratching or otherwise damaging the groovesA tool for cleaning the ring grooves can be made from broken ring with sharpened edgeCare must be taken not to damage the lower ring landsSee Figure 5-25Check piston for size and roundness using micrometerSee 5-30Correct sizes are given in Section 2Before installing new piston rings, check gap between ends of ring by placing ring in its respective cylinder bore, then pushing ring down in the bore slightly with the bottom of the piston to square it upSee Figure 5-26Check for ring groove clearance with feeler gageSee Figures 5-27 and 5-28Correct gap and groove clearances are given in Section 2WARPED RING INSUFFICI ENT GAP WORN RING GROOVES