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Before assembling back lower tail, must lightly grease drive shaft upper splines, if with difficulties inserting shaft onto crankshaft, turn flywheel by hand CW while pushing lower tail upward untill lower leg is fully inserted under middle leg, Check water pump grommet has made a good marriage with upper water tube or won't see engine peeing. The size is not mentioned in the spare parts manual, so any Samaritan having them apart should chime in to provide proper measurements for them.
Happy Boating