2006 Johnson SD 30 HP 4 Stroke Outboards Service Manual, PN 5006592, Page 163Get this manual
POWERHEAD PISTON, CYLINDER, AND CRANKSHAFT Remove eight (8) outer bolts, then eight (8) inner boltsRemove the crankcase from the cylinder block
Selecting Main Bearing
Whenever main bearing requires replacement, select new bearing according to following procedure Check the main bearing journal diameterThe upper (flywheel side) crank web of the No.1 cylinder has four (4) stamped numeralsThe numerals 1, 2, and represent the following journal diametersNumeral Stamped
Main Bearing Journal Diameter
1Outer bolts (8) 2Inner bolts (8)
1.5746 to 1.5748 in(39.994 to 40.000 mm) 1.5743 to 1.5746 in(39.998 to 39.994 mm) 1.5741 to 1.5743 in (39.982 to 39.988 mm)