This unit bolts to the engine flywheel much like a pressure plate or clutch cover in an automotive application. Its construction includes an aluminum case, rubber insulator and aluminum hub. It fails due to the engine being out of alignment with the gimbal housing or with lack of lubricant. The aluminum splines should be greased every year. The steel yoke assembly which is inserted into the aluminum hub causes aluminum to strip without lubrication.
MERCRUISER ENGINE COUPLERS
18-2171 Replaces 76850A2 For all GM engines except MR/ALPHA/BRAVO with "triangular" 3 bolt coupler.
18-2175 Replaces 18643A7 Triangular style, Flex plate style for late model, small crankshaft bolt pattern style engines
18-2195 Replaces 12632A7 Flex plate style GM 4 cyl. w/ late style, small crankshaft bolt pattern