1970 Evinrude Ski-Twin, Ski-Twin Electric 33 HP Service Manual 4687, Page 44Get this manual
or flanges are employed and are subject to temperature changesTo check for flatness, lay sheet of No120 emery cloth on surface plate or piece of plate glassPlace the part to be surfaced on the emery cloth and move slowly back and forth several times in figure motion, exerting evenly distributed, light pressureSee Figure 5-16Lift part from surface plate to observe resultsIf the surface is actually warped or sprung, high
fReplace top crankcase bearing seal and "0" ring