Mercuiser Bravo 3 Water Pressure Question

[bengaltiger14]

What is the normal water pressure for the Mercruiser 5.0L MPI Bravo 3. After impeller change, mine is idling at 10-15 psi and getting up to 40 psi when cruising at 30 mph. This seems too high. The engine temp will rise to 170 and sit there until I slow down, then it begins to cool. Any ideas?

 

[Fun Times]

Typically you will see at idle/low RPM between .5 - 5 PSI while mid range would be around 7 - 10 PSI and full throttle could be 11 to 17 and maybe as hi as 20 PSI. Some boats may very while I have seen reports online as high as 25 PSI.

If anything was to be wrong it could be something like a slight restriction at the transom water intake fitting, a bad sensor, bad wiring connection at the sensor.

170 degrees would be normal as you have 160 degree thermostat.

 

[bengaltiger14]

Before I replaced the impeller, it was reading about .5 to 1 psi at idle and around 10 psi max at mid range.