You said in a previous post that the water flow was great after the impeller change. Are you now saying that it has changed and the flow is now much lower? That engine is not a great water producer at the best of times as you will see in this chart and these figures are based on top notch condition engines.
You will receive better information (and not frustrate those trying to help) by keeping all your related posts in a single thread.
If you are running the motor on muffs, the gauge won't read, even with a brand new pump/impeller. Running in the water at idle you should expect about 2-3PSI and at WOT not much more than about 12-15PSI.
