An engine survey should be part of your purchasing process.
If the engine is sound and in good condition than it should not be an issue. I would not think twice about it on board our boat and frankly if the engine could not be expected to do a little motoring than I would not bother with the purchase.
Courtney is My Hero
If a man is to be obsessed by something, I suppose a boat is as good as anything, perhaps a bit better than most - E.B. White