I assume you mean the cost to remove and replace the engine in your boat. In Southern California in 1999 a higher priced yard charged me 4.1 hours at $65/hr to remove the engine and put it in my mechanic's truck, plus a crane charge of $150, for a total of $416., but that also included picking up and returning the boat to my mooring.
For putting the engine back in they billed 3.7 hours at $65/hr including alignment, reconnecting exhaust, etc., with the crane charge the total was $390.