1976 Evinrude 40HP outboards Service Manual, Page 51Get this manual
(2) Fractured ring This may be caused by forcing cocked bearing off shaft, or by too heavy press fit(3) Worn, or scuffed surfacesThese may be caused by too loose fit, or bearing locked by dirt and turning on shaft or in housing(4) Badly discolored rollers and races This is usually due to an inadequate supply oflubricantModerate discoloration is not cause for discardfReplace top crankcase bearing seal using OMC Special Tool (Part No316613) Replace "0" ringFigure 5-18Surfacing Cylinder Head gLower crankcase seals should be replaced and any parts of this assembly should be replaced if damaged or wornSee Figure 5-10Use OMC Special Tool (Part No319925) to replace sealsSeals are installed back to backPISTONS Check the pistons for roundnessexcessive skirt wear, and scoringCarefully remove carbon deposits from inside of piston headInspect the ring grooves for carbon accumulation, excessive wear, or damage to the ring seatsNote that the upper ring groove is tapered for the pressure backed ringSee Figure 5-19Carefully scrape carbon from lower ring groove, making certain that carbon Clinging to the bottom and sides of the groove has been thoroughly removed without scratching or otherwise