Mercury F1AZ-6303-AARM Crankshaft Assembly

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Starting with the center main and working out toward the ends, tighten the main bearing cap bolts, in three steps, to the torque specification.

Push the crankshaft all the way to the rear and zero the dial indicator. Next, pry the crankshaft to the front as far as possible and check the reading on the dial indicator. The distance that it moves is the endplay. If it's greater than the limit, check the crankshaft thrust surfaces for wear. If no wear is evident, new main bearings should correct the endplay.

Check the rest of the crankshaft for cracks and other damage. It should be magna fluxed to reveal hidden cracks, a procedure typically handled by an automotive machine shop.

Remove all burrs from the crankshaft oil holes with a stone, file, or scraper. The oil holes should be chamfered so sharp edges don't gouge or scratch the new bearings.

Remove all side bolts.

Make sure the crankshaft journals are clean, then lay the crankshaft back in place in the block.