I have a 1960 Merc 300. It was originally owned by the family who owned the Mercury dealer in Salem, Virginia. It appears to have been well cared for and was only used in fresh water. I figure that when it was serviced, the mechanics knew that it belonged to the boss, so they knew they better get things right.
My questions:
What is the thread specification for the three holes on the flywheel where the puller bolts thread in? They appear to be 5/16″ diameter but neither fine pitch 5/16-24 nor coarse pitch 5/16-18 seems to thread in. I cleaned the holes but still no luck. I don’t want to force something in and mess up the threads. If I know what it is supposed to be I can chase the threads out with the correct tap.
On the gearcase there is a hole marked “Flush” but it appears to be the vent for the gearcase lubricant. Is this the vent screw? It is a large screw like the drain screw with the little round gasket. I can’t find any other screw that might be the vent. I opened both the drain screw and the “Flush” screw, but no lubricant came out. There seems to be grease inside, something like Lubriplate. There is a small flathead screw just below the cavitation plate. I have not removed that screw. It is possible that it has all leaked out over the years? No water came out, thank goodness. The unit shifts nicely.
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