My 1988 Mariner 50 needs a tilt trim assembly. The shaped letter on the existing system is GH04 A37. I bought a used one, being told it will fir .. it did not. So now I want to make sure I get this model. My question is this the part number, or is there a part number for this assembly? It's a 3 wire system. Or is there a reputable company that will get me EXACTLY what I need?