New to this engine (1972, 40hp, 402 thunderbolt) and want to change the cooling system impeller. I loosened the one nut (thats all there is) from each side, and took the one off in very back, This has loosened the lower unit off on the front side but still seems to be solid on the back side above the propeller. I,m thinking that the trim fin above the propeller is holding the lower unit up solid. My question is how do you remove this trim fin? there is a hole directly above this fin but unable to get a socket (1/4" or 3/8" drive) through the hole that is big enough to remove what might be a 9/16 nut. On the fin itself there are no nuts or bolts to remove or loosen this. Any suggestions
