1969 Evinrude 40 HP Big Twin, Big Twin Electric Lark Service Manual 4596, Page 74Get this manual
Figure 6-36Checking Parallelism gInspect gearcase for nicks on the machined surfacesRemove nicks and re-surface faces on surface plateStart with Number 120 emery cloth and finish with Number 180 emery clothCheck parallelism on plate with surface gage and scriberA drill press table will also serve, using the spindle as gageSee Figure 6-36DO NOT attempt to straighten bent gearcase; replace ithRe-surface and inspect exhaust housing in like mannerReplace if bentNOTE bent exhaust housing may cause upper driveshaft splines to wear excessively, and may also damage crankshaft splinesiInspect water tubes for obstructions or kinks which may restrict water flowjInspect water pump impeller and replace if vanes are damaged or worn excessivelyInspectpumphousing for scoring and replace if damagedInspect impeller housing plate and replace if scored or pitted 25 4