What should my water temp be running on a 96 454mag efi? It seems to take forever to warm up and then reads about 125 until ?I get on it. Then runs about 150

Sounds your thermostat isn't present or it's not working. My efi 454's are fresh water cooled and specs say 160 degree stat--raw water stat is 140 degree.

Mine run aroune 150-160 at cruise (3200RPM) kick up to 170-180 at WOT.

Boat is a Formula SR357 with TRs drives and weighs over 10K. Engines are MarinePower 454 EFi using Arizona Speed TPI.

I'll ditto that.... Sounds like thermostat is stuck open and allowing continuous water flow to the engine thus preventing it from warming up to where it should be... The thermostat is an easy swap out..... just yell if your not sure how to..... Good luck!

tHAT IS WHAT i THOUGHT IT WAS. i HAVE A COUPLE NEW ONES IN THE GARAGE. THANKS