Re: Merc. 115 Circa '77
3DMix, My '77 froze up a couple of times when layed up. It was always due to water from the cooling system entering the cylinder. It was easy to free up, oil and a tap on the piston through the spark plug hole. Then hone and new rings. Make sure you find out why it rusted up and fix it. Also, mine was always a single cylinder that rusted, the others were good. The hard repair was to find the water leak (usually the inner water jacket under the exhaust water jacket cover), and fix it.