1978 Johnson 4HP outboards Service Manual, Page 61Get this manual
performance of the engineBefore reinstalling the pistons, break the glaze by using fine cylinder honeUse low rpm on drill with rapid up and down movement to obtain good crosshatch pattern for good oil retention Use hone with medium stone (220 grit)GASKET SURFACES Remove all traces of dried cement from gasket surfaces, using trichlorethyleneCheck 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 changes8303 5
Figure 5-13Surfacing Cylinder Head