2008 Evinrude E-TEC 55MFE Technical Manual, Page 197Get this manual
POWERHEAD POWERHEAD INSPECTION The dimensional difference between the two areas is cylinder taper The cylinder taper must not exceed 0.002 in(0.05 mm)the cylinderUse feeler gauge to measure the ring end gap
002143 1Measurement areas DR3482
Ring end gap should be: 0.011 to 0.023 in(0.28 to 0.58 mm)
The difference between the measurements and standard bore is cylinder oversizeFor dimensions, refer to SERVICE SPECIFICATIONS on p8 The cylinder must not be oversized by more than 0.003 in(0.08 mm)
IMPORTANT: Ring end gap increases approximately 0.003 in(0.076 mm) for each 0.001 in(0.025 mm) increase in cylinder bore diameterDO NOT exceed cylinder oversize dimensionUse machinist's straightedge to check for proper ring clearancePosition piston rings on pistonPush rings into groove and hold straightedge against the side of the pistonRings must be even or just below the surface of pistonRings must move freely in piston ring groove