questions about temp warning sender 7.4 MPI
 

working on a 7.4 MPI that I pulled out and put in so the transom could be replaced. got it fired up today and it is giving me a code 14 for coolant temp. engine idles on the hose at 170 water temp. does the temp sender that works the alarm an on or off, or does it read actual temp and the ecm decides to set the alarm? the only history I have on this boat is that he had an impeller put in and they hooked the hoses backwards and shredded it so they then put another in and he says it has run hotter than normal since then. two years ago he backed into a slip and wedged a piece of rebar between the two props (bravo 3) and it has been sitting the last two years till the repairs now. also, how long will the ecm hold codes with no power?