I recently installed a working water pressure gage to this engine. The water pressure reads about five psi and will get up to about 11 psi if I revved the engine in neutral to fast idle . The stream coming out of the back of the engine, what I call the P whole is shooting a strong stream of water down into the lake that goes about 2 to 3 inches deep into the water. The impeller is probably six years old , And I am going to replace the impeller, but I'm curious what other gauge pressure's for a 90 Yamaha should be. Most of the stuff I have read says that most water pressure should be around 15 what are your all's thoughts