Variance in water pressure

[YellowT]

I have a 2022 Mercury 150 four stroke with 72 hours. A friend with more experience with powerboats (I've been a sailor and kayaker mostly) has expressed concern about the variance in water pressure.

At idle, water pressure holds steady at 6 psi. At cruising speed on plane, water pressure varies between 11 and 16 psi. The variation is quite short; the Smart Gauge bounces 2 or 3 psi up and down in a second or two, over and over. However, engine temperature remains steady between 124 and 129F. No overheating.

I'd assumed that the sensor was being polled about once per second and the overall 4 or 5 pound variance resulted from the thermostat opening and closing, and/or small intake differences relating to waves and chop. My friend says the sensor is bad or the poppet valve (?) isn't closing properly. Hmmm.

Any insight, confirmation for or against, etc. on this? Thank you.

 

[dingbat]

I have a 2022 Mercury 150 four stroke with 72 hours. A friend with more experience with powerboats (I've been a sailor and kayaker mostly) has expressed concern about the variance in water pressure.

At idle, water pressure holds steady at 6 psi. At cruising speed on plane, water pressure varies between 11 and 16 psi. The variation is quite short; the Smart Gauge bounces 2 or 3 psi up and down in a second or two, over and over. However, engine temperature remains steady between 124 and 129F. No overheating.

I'd assumed that the sensor was being polled about once per second and the overall 4 or 5 pound variance resulted from the thermostat opening and closing, and/or small intake differences relating to waves and chop. My friend says the sensor is bad or the poppet valve (?) isn't closing properly. Hmmm.

Any insight, confirmation for or against, etc. on this? Thank you.

The water pump is a fixed displacement pump. Output flow and pressure vary with RPM.

To keep pressure and flow stable, they use a pressure/flow relief valve called a poppit valve. The Poppit is in effect a spring loaded vent, that dumps excess pressure/water to the exhaust housing to maintain operating pressure. The pressure bouncing around a bit is perfectly normal operation.

 

[YellowT]

The water pump is a fixed displacement pump. Output flow and pressure vary with RPM.

To keep pressure and flow stable, they use a pressure/flow relief valve called a poppit valve. The Poppit is in effect a spring loaded vent, that dumps excess pressure/water to the exhaust housing to maintain operating pressure. The pressure bouncing around a bit is perfectly normal operation.

Understood. Thanks for replying.