I'm surprise no one else has tried these, unless they read this first.
That said,I have yet to get one that works as the original Mercruiser one.
Given they read 40.4 psi, I suspect they are 0 -100 psi (oil or
fuel sensors) and not 0-50 psi (water)
Some more data FYI
The 881879-11 pressure sensor is used on many
Mercury Marine and Mercruiser
engine models. MotoTron also used this sensor across many customer applications. This sensor is a -4.7-100 PSI, with a burst proof pressure rating of 150 PSI and a rated burst pressure of 500 PSI. Vout = 0.04 (PSI in Absolute) - 0.088. I added the pin out of this sensor in pictures area so that you can diagnose your sensor prior to replacing it.
The 881879-10 pressure sensor is used on many
Mercury Marine and Mercruiser engine models. MotoTron also used this sensor across many customer applications. This sensor is a 0-50 PSI, with a burst proof pressure rating of 100 PSI and a rated burst pressure of 325 PSI. Vout = 0.08 (PSI in Absolute) + 0.5. This sensor supersedes 881879-3. Sensor 881879-10 will also
work as a replacement to 8M6000623.
These sensors are very robust. I have seen on applications where these sensors are mounted on closed
cooling heat exchanger on Mercruiser engines where excessive static charge built up on the tank due to the flow of water and routing of spark
plug wires, energy would dissipate through sensor and cause the sensor to fail. Make sure your
heat exchanger is grounded!
There are 3 pins on the connector A (BLK/BRN). B (GRY) and C (BK BLU/YEL)
Readings should red as follows at 70 degrees
A to B 31.5 ohms
A to C 42.9 ohms
Grey is the 5V
power feed, Blk/Pk is the 5v ground lead and the Dk blue/yel is the reference lead to the computer.