Larry, do you have an oil changer on your boat? As I commented earlier, there is really no reason to put one of these valve on a 53MY unless you do not have an oil changer. If you don't have an oil changer, I'd recommend one; they make oil changing almost a non event as long as you have/get one that can pump cold oil (new oil back into the motor).
Mine had trouble with cold oil but I found the problem was not the pump per se, it was that hose used for pumping oil back into the engine was too small. One size larger ID hose/fitting took care of the problem.