I don''t know for sure, but considering how you have to be careful when loading a boat so as to not upset the balance or overload it, I would venture to think that a 4 cylinder cast iron engine block and the rest of the parts have enough weight to cause an imbalance when removed. If the outboard will be close to the same weight I don''t think there will be a problem. You may have to put offsetting weight in the hull to counterbalance the lack of weight. Sailing the boat will tell you if you are out of balance. Just a guess on my part.