I was riding around sunday and hit bottom in the preocess I picked up an piece of nylon rope around prop and it must have had an metal hook or such on it....it broke an piece out of the gear housing above prop just below the cavation plate. how critical area is this . I ran it 3 miles back in an no overheat. what is it going to hurt if I don't fix this? guess an piece about 2 inches long along the rear edge of lower unit maybe going forward 1/2" or maybe 3/4"