low psi on 225 mercury

fishing last weekend and notice my digital water pressure was at .5 at idle thought that was bit low the alarm did beep once and that's what got my attention going across
the lake its at 15 to 18 psi at around 50 mph fish all day no alarm but psi was .5 to .8 at idle. had the pump changed this week went to day and its now 1.2 to 1.5 at idle the
old pump look new and its less than 2 years old with about 100 hours on it.i thought it should read around 5 psi at idle hope i did not waste money on water pump if something
else wrong. any ideal

Might check under cowl for evidence of water leaks especially around lower power head mount bolts.

everything is dry i had the same mech. do the pump this time he has done all the maintenance on the boat every two years
this year he just didn't seem to interested in my problem.i have a optimax with the smart technology was just thinking is there
a water sensor also.

Normal psi on opti at idle. Need to change pump once a year