2003 Fountain Fever 29 with 525 blue block. I had a mechanical failure on raw water pump. On last trip out at time of failure, Water pressure was running about 10lbs greater at cruising speed than normal. Water pressure gauge started fluctuating between 10 and 40lbs at 40 mph and pump failed. Pump seized but impeller was not damaged. Replaced water pump with new HARDIN SS pump due to its known durability. Water pressure runs at 4lbs at idle now and never exceeds 35lbs at rest. While underway water pressure is extremely high. Prior to replacing pump, WOT 5250rpm water pressure ran around 40lbs. Cruising speed averaged around 30lbs. Now cruising speed is 40-50lbs. If I run greater than 45 or 50 mph the PSI is greater than 50lbs. I have cleaned my front heat exchanger, my power steering pump cooler, my header drains have been flushed. Boat has never been run hot. Runs 150 degrees consistently. Top hose on Raw water pump seem extremely tight while running. What are the symptoms of a bad pressure sensor? Have not been running boat for last two weeks due to fear of causing damage due to my lack of knowledge on the Mercury 525 blue block.