You really do not have enough information to make a good decision. As others have said what exactly is the replacement engine?? Forget about the hours because a rebuilt block from a competent rebuilder should start the clock from zero. The trick is to determine if it was from a competent builder. The dealer probably just made a honest mistake so don’t just trash him without knowing the full story. Also a engine with just 40 something hours on it over 9 years might be suspect in itself...if the original owner didn’t use it much probably didn’t maintain it much...the rebuilt might be better than the original..finally when you go to sell it hours unless extraordinary are inconsequential. Find out the facts you might be leaving a great deal for someone else. This setup will run for years if in fresh water..if saltwater outboard only..ps. The dealers insurance should pay for this screw up and most likely would pay for a new engine so push on that...
