I verified with an EGT probe on the front engine case, the NEW YAMAHA supplied THERMOS SENSOR / Switch the one in the front that does not give Code 15 but when activates causes your engine to go into LIMP MODE, was triggering at 144.7 degrees F. YAMAHA Sepc for this device is 183 Deg - 194 Deg.

I pulled it out again and put into the Freezer for 3 hours, removed it and Smacked it on the Wall like a whip motion. I retested it in hot water and now it activates at 190.4 deg's F and opens back up when cooled at 163 deg's F.
I used this method to reset the Over Heat Thermal Disc in DYERS, It works.
I have also pulled ever line and fitting out, FLUSHED and Back FLUSHED, I pulled the Exhaust completely apart each piece and used a piece of Speedometer cable to Snake through every port verifying they were clear. FYI using this cable, turn in the counter clock wise direction so the strands do not bundle up *** you have been warned.

I found a lot of high grit sand in the lower rear Exhaust pipe, I will pull the head to verify the water jackets are clear or have sand packed around them, then reassemble and RUN THE CRAP OUT OF IT!

I will be leaving the EGT Probe mounted to the Center Front of the engine block to monitor the actual Engine Block temperature.
I will be installing an IN-LINE water Separator for the future. I also will Splice into the ROOSTER TAIL water and redirect some of the flow into the supply feed line to the engine to offset the PSI drop using the in-line separator. This will increase PSI on the Exhaust side due to no restrictions, PEE PORT should SHOOT WATER not just Spray, on the engine side the restrictions are built in and the Thermostat creates back pressure / Flow so the increase in PSI does not Blow through the engine side causing a heating issue. Water in / Water out only PSI changes on this side.
Any one else use a Separator or the Rooster Tail Water in this fashion?