Poppet opens when?

[ZO6]

What makes the poppet valve open on a 2005 250 XS OT999026. At what temp, speed or PSI makes the poppet valve open? Or is it a combination of these factors? How do you know it is open and closing reading smartcraft/mercmonitor?
My temp is staying at about 120 degrees rising to 124- 130 depending on RPM/speed never goes above 130 even WOT 15/17psi. Thermostats are clean and working. Getting about 8/9 psi at 30. 10 psi at 40. Water temp is 79/81 degrees.
How do you know if the poppet valve doesn't open or stays open?

[Shef]

I have the same engine serial #ending with 041. Your numbers are right in line with mine. We have 120 degree thermostats not the 130s. I

[EuropeanAM]

Poppet valve opens via WATER PRESSURE. Spring setpoint is at approximately 7 psi (=/- 0.5 psi).

Normally, as the engine reaches APPROXIMATELY 2000 RPM's the poppet valve is opening, allowing a FULL flow of water through the block.

Thermostats control water flow ONLY AT IDLE. At planing RPM's, the POPPET VALVE controls water flow... and the thermostats are essentially just "along for the ride" until the engine again returns to IDLE SPEED.

[ZO6]

Thanks Don! That is what I wanted to know!