I have an OMC w/f filter sep. housing on my boat. The # is 124396. It has 1 "to" and 1 "return". The one it shows in the Seloc repair manual shows 4. 2 "inlets" and 2 "outlets". I'm wondering if the one I have in the boat is correct, or does it matter. The filter is a Sierra Filter # 18-7846 What are the diffences please. Engine is a Mercruiser 5.7 Gen 1 Thanks