1985 OMC 65, 100 and 155 HP Models Commercial Service Manual, PN 507450-D, Page 188Get this manual
Gasket Surfaces Remove all traces of dried cement, using OMC Gel Seal and Gasket Remover Part No390928I using Gel Seal and Gasket Remover, spray the area to be cleaned and let stand for 5-10 minutes before cleaning off the removerCare should be taken to prevent overspray of Gel Seal and Gasket Remover on painted surfaces as the paint may be removedWear eye protection and rubber gloves or other nonporous hand protection while working with Gel Seal and Gasket Remover ill
Check all gasket faces for flatnessUnder certain conditions, gasket faces may warp or spring, particularly where thin sections 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 pressureLift part from surface plate to observe resultsIf the surface is actually warped or sprung, high spots making contact with the surface plate will take on dull polish, while the low areas will have retained their original stateTo insure flatness over the entire surface, continue surfacing until the entire gasket surface has been polished to dull lusterFinish surface with No180 emery clothrN=t=llf cylinder block or cylinder head requires resurfacing the total of material removed must not exceed .254 mm(.010") rN=t=l DO NOT scratch cylinder head gasket surface of cylinderUse surface plate to surface this areaINotel DO NOT re-surface crankcase halvesIf distorted the cylinder and crankcase will require replacementCrankshaft Seal Rings100 and 155 Models Check crankshaft seals for excessive wearSeal rings should fit snugly in cylinder block and crankcase, and should form tight seal around crankshaft websCrankshaft Bearings Check upper needle bearing and center main bearing liners and needles for wearCheck lower ball bearing for roughnessIf bearings show excessive wear, replace