I would not stress a lot in regards to the fin on the bottom, just seal it up so it isn't going to leak. Ironically I welded up a lower unit just two times back. Dude hit a rock and punched a hole from the front of his unit, dug https://louistbqvg.daneblogger.com/30841532/an-unbiased-view-of-marathon-lower-unit-repair