I have a 1992 50 HP 2 cyl 2 stroke outboard that had the power head replaced under warrantee by the original owner. The boat has a very comprehensive gauge package and the water pressure gauge has never worked in the time I have had this boat/mtr. There is a 1/8NPT boss with a 90 deg plastic fitting which connects to the water pressure gauge. This machined fitting is blind (ie goes nowhere, but is tapped and the 1/8npt to barb was in place). Looking at the back of the motor it is located between the bottom left and next further left cylinder head bolts for the top cylinder. Is there a service bulletin or any literature on what must be machined or drilled to activate this gage port?? Or perhaps someone would have one similar and could take a picture or describe it for me. I have found several pictures of this head, but never with adequate detail to see what I need to see. 
Thank you very much.....
Thank you very much.....