I have 2 454 mpis and one motor is consistently running hight water pressure that the other. At 4500 rpm 1 is at 25 psi and the other is at 30-40 psi it bounces a lot but at idle both run the same psi 2-3. The same motor with the high water pressure will steam at idle after running and runs about 5 deg warmer them the other. They both wave new sea pumps, thermostats, and themp senders for the efi. I have taken every hose off and back flushed each motor completely and have found no restrictions or debrese. If any one has any suggestions on what to do it would be appreciated. Thanks Eric

Have twin 6.2's with smart craft gauges, backed up with mechanical gauges.With brand new impellers in the seawater pumps, never observed pressures higher than 26 psi at WOT and low readings are 1-2 psi at 600 rpm idle. Wonder if there's still some outflow restriction in the system.

sounds like restriction at oil cooler,sometimes just flushing wont get all the small pieces out.i would remove cooler and get a good visual.

My pickup for the water pressure is after the oil cooler do it can't be from it. Also I have done a visual on it and it is clean.