1985 OMC 65, 100 and 155 HP Models Commercial Service Manual, PN 507450-D, Page 231Get this manual
10Remove the crankcase to cylinder block screws11loosen but do not entirely remove the four screws holding lower bearing retainer plate to lower crankcase headTap crankshaft with soft face mallet to break seal between crankcase and cylinderReplace one by-pass coverUse cover to pry crankcase halves apartCrankcase may be removed to expose the crankshaft and connecting rods for further disassemblyIN-t=llf servicing only the crankshaft and main bearings, install the cylinder heads to prevent the piston and rod assemblies from slipping out of the cylinder block while removing the connecting rod capsCrankshaft, Connecting Rods and Pistons
Pistons, connecting rods, rod bearings and bearing retainers are wearing parts and seat with the operation of the engineBecause of this, it is essential to maintain their original positions at reassemblyMark each connecting rod and cap, piston and bearing component to assure correct mating when they are removed and keep the needles of each cylinder together1Remove connecting rod cap screws, caps and roller bearing assembliesA 516 inch 12-point deep socket is required for removing and tightening connecting rod cap screws (discard cap screws)INotel18 rollers are used at each crankpin