MG Car Repair: 1979 MGB, coolant level, o reilly parts

Question
QUESTION: Replaced temp sending unit in head, and now temp gauge reads hot. Put in new 165 thermostat, and still reads hot. Hooked up a temporary gauge to new sending unit from O'reilly parts and it read 225 degrees? Doesn't boil over or steam, coolant level is good. Thank You

ANSWER: Hi Roger,
The temp gauge is not powered by 12v. It is powered by a voltage stabilizer mounted on the fire wall behind the instruments and it has an out put of about 10v. Also, if the charging system is not correct it could effect it also. Check across the battery at 1500 RPM to be 13.8v to 14.5v.
Howard

---------- FOLLOW-UP ----------

QUESTION: Thanks for reply Howard. Should I put in 185-190 thermostat? Could this make it run cooler? Or what about a new 15# radiator cap? Thanks again, Roger

Answer
Roger, why do you want to put in a hotter thermostat when you say it is too hot now??? You said it does not boil over so did you check the actual temperature of the coolant with a meat thermometor? Did you do any of the things I told you to do?
Howard