Yanmar Oil Presure Sender - replacement for Faria gauges

[KJFPAF]

Does anyone have experience replacing the Oil Pressure Sender on a Yanmar 6LP with Faria gauges? The needle on my gauge starts to fluctuate 30 minutes into a trip; the needle swings rapidly from 55 to below zero PSI. The engine temp stays where it should be at about 180 degrees. My research so far points to the sender. So I removed the sender, and got a new Faria sender.

The problem is that the sender needs a male 12 MM 1.25 (or 1.5) thread yet the Faria sender is a 1/8 NPT thread size. So the sender I removed could not be the Faria, yet it appears to ALSO NOT be the Yanmar because Neimac marine in New Bedford showed me the standard Yanmar 6LP sender replacement unit which ALSO has a different male connector thread (not sure what it is, but it is much narrower than 12MM).

The motor is a 2006: 6LPM-STP. Attached is a pic of the old and new senders (and an adapter of the wrong size - appears I need 12MM to 1/8 NPT which is NOT easy to find...).

Any insights will be greatly appreciated!
Thanks,
Kevin

 

[KJFPAF]

Wrong sender - engine temp rather than oil PSI

I solved the issue; I removed the engine temp sender rather than the oil PSI sender. I don't know why the temp sender has a 12 MM thread while the Oil PSI sender has a 1/8 NPT thread as they are about 2 inches apart.

FYI to anyone with a 6LP and 2 senders to port; the aft sender (gold color on my motor) is the Oil PSI while the forward sender (gray) is the engine temp.