Fluctuating Oil Pressure- Bad Sender

[four winns 214]

The oil pressure indication on my Merc 228R I/O was fluctuating 5-10psi. This engine is 30 years-old with 775 hours. I feared the worst, but carefully troubleshot the issue and discovered the cause was the oil pressure sender. It was easy to replace and now my oil pressure is steady. I thought I would share this information for the corporate knowledge of other owners with similar elderly engines. I had several people tell me senders rarely fail and that it was probably the gauge or that the engine oil pressure was actually fluctuating. Oil pressure senders DO at times go bad.