2 questions

i have a 95 201 pro xl with a 99 model 225 merc .first tattle tale not pumping water even though I have great water pressure. my gauge only goes to 15 lbs but it bottoms out at wot. checked to be sure the outlet was clean and wasn't plugged. should I be worried about this?
second what is the best prop for this set up? i'm running a 14by25 high five and the fuel economy is terrible. wot 5950 so I back out of it a little and running 64 loaded. I know there are a lot of variables. just looking best performance and possible a little more speed.
thanks

Pull the cowling and check for a clog on the hose between the P hose and the motor. Those motors do not do well on fuel. You can gain speed with a 25 pitch Fury or Tempest but you may not like the planning time.