2016 250 SHO with 350hrs
On long WOT (6,000rpm) runs the temp will start climbing. It will sit at 140-145 degrees for a while but then starts creeping up. It has not hit the threshold for an over temp alarm, but I have seen 197 degrees before backing off. Once backed off the temp will come back down to normal operating temps (under 145). Temp stays below 145 degrees under 5,000rpm. It is consistant and repeatable with enough distance (10-15miles).
I've had the engine since new, temp was never a problem and always stayed under 148 degrees, even on 45+ min run (50+ miles).
It starts and runs fine. Fuel usage is still same/similar as new.
I had it to the shop, they looked at the computer (no temp alarms), and ran it but was unable get it over 140's without being on the water.
Thermostats have been replaced by me (old ones tested fine)
Water pump was replaced by me (old one looked fine)
Whole Waterpump and assembly was replaced by shop
Water pressure at WOT is over 25psi
Has anyone experienced this?
Looking for ideas where to begin.