motor getting alil worm

i just put a new motor in my 92 toy and it runs alil worm it moves from right under 1/2 and right over 1/2, but it never ran this worm befor i have a 180 t stat in it just like i had in the other motor and i jst bought a new raderatoer cap but it still gets too worm for me, it used to run at about 1/4 so what can i do to get it down? do they make a 165 t stat for the 22re? any good help will be helpful...