2003 Yamaha 200hp FI Low water pressure

Noticed low water pressure on gauge after starting engine. Alarm went off, shut down engine. Replaced water pump asm. and started engine back up, still low water pressure, pressure goes up to about 5 lbs. when increased RPMs. Took off water pressure line at engine going to water pressure gauge, no water coming out of connection. With water from hose turned up to higher pressure, the engine doesn't over heat and no alarm. Is water suppose to come out of head at gauge connection?? And what should I look for. The old water pump was not in bad shape, no broken vanes.

Check the pressure control valve. Maybe stuck open. Also could be a broken or corroded off water delivery tube.

If you are running it on a hose, expect it to overheat. Yes water should come from the engine connection for the tube going to the guage. It may have a bit of sand in it. Put the engine in the water at the boat ramp and try it again, see if it overheats. Blow through the tube going to the guage, with it off the guage. Blow back into the fitting on the engine where the tube goes to blow out any sand or other crap that me inside of it.