When I bought my ride 2 month ago, the sender for the inside helm gauge died. The end connector on the gauge butt just went. Off and I was unable to fix it, so I searched for a new one.
I do not bknow on your engine but on mine it is pretty simple and it is kinda like plumber. The engine port for oil pressure isnfitted with a T and 2 sender are screwed, one for upper helm, one for lower helm.
The only thing I needed to care about was the gauge max scale, some sender are for 80psi max gauge and some are for 100psi max gauge. I ordered the part from marine outfitters in Kingston ON and itb was a 5 minutes job to replace it. Unscrew the old one, screw the new none, connect the wire and here we go.
From my search I know that some engine have specific senders but old engine generally use the same as the one I needed. If you post a picture of your sender I can tell you if it is the same as mine.
By the way when the sender fails, the symptoms is that the gauge is going nuts showing the extreme max as the sender and gauge are based non resistance, when the sender fails resistance is at its maximum.