looking to buy a 1993 14'boston whaler RAGEwith an omc mod 90jeer sn.go3561784 with a san leandro jet drive first time i had it out the hitemp alarm sounded. left boat over nite and in the next morning it ran like a dream all day. next day after 4-5 min hi temp alarm sounded again.let cool and tried again,alarm again removed themostats and tested opened from 135-140 checked flow from heads at an idle they both flowed equal amounts of water after about 15 sec.do i buy it or is this a fixable problem.it looks like this combination may have died out for a reason . 
thanks.
thanks.