temp. for 1992 Mariner 150 Magnum II

[avian22]

WoW!

If 150 should be my running temp. I have a long way to come down. My gauge reads about 135-140 under 3000. When I "Put it down", it goes up to about 190-200 and stays there (never over heats). Weird! Gives me the feeling that it's about to start overheating, but never does. Maybe my temp. gauge (which is new) is not reading correctly.

I am going to change my t-stat (which hasn't been changed in over 5 yrs. And, I'm going to flush it with some "Salt-away" (salt remover).

Question: Is the "poppet valve" different than the T-stat or is it "part of" the T-stat?