Well I suppose the biggest problem could be that the engine falls to the bottom of the hull and tears a hole through it and you sink. Shafts can become misaligned and you can twist those off. The exhaust system could be torn loose. Excessive vibration of the vessel which could cause your favorite beverage to fall into your lap.What are the problems that can occur with a bad engine mount? How is the problem fixed, are there any other problems this can cause to other areas of the boat? engine itself, gear, shaft, etc?