water pressure gauge 150 merc

[jarhead624]

ok , I replaced the water pump, poppet valve and t-stats, then I installed a water pressure gauge, the readings I get are as follows at idle it reads about 2 psi between 2000-3000 rpm it reads abot 6 psi and at wot it reads 10 psi
from what I have read in this forum that seems low, any thoughts? its a 2003
150 saltwater series

 

[Chris1956]

Re: water pressure gauge 150 merc

That is a bit low. You should replace the impeller. I think you shoud have about 15PSI at 2/3 throttle

 

[gss036]

Re: water pressure gauge 150 merc

Factory Mercury OEM manual usually has the mortor listed at Idle/low rpm 2 PSI to WOT at 12 PSI. You are not that far off. Where/how did you hook up the tap on the engine? Should be plumbed into the outlet at the top of the block, just behind the flywheel.

 

[hkeiner]

Re: water pressure gauge 150 merc

The advice I was given when I installed my water pressure gauge was to replace the impeller at the same time and then check the pressure gauge readings to establish a baseline "normal" reading and confirm that it is within the OEM specs. If one sees a subsequent drop in the readings from tne established "normal" reading, then consider this as an indication that the impeller is starting to fail or a blockage has occurred.