I would think that if the stats were stuck open, the motor/under the hood avg. temps would tend to be on the cooler side and perhaps then making the rec live longer. Not so sure the two relate thou.
I don't know Johnson's motors, but I do know someone that does on TV so take it for FWIW...........
Right part spec'd back in? Chinese knock offs aren't so good syndrome ......
Properly mounted?..i.e., it requires ample heat xfer perhaps w thermal grease even
Is it possible its being over loaded? Too many hot tubs and such
Have you checked AC supply potential (loaded/unloaded) to make sure you're in spec'ish? Stator good and such
AC/DC current flow? Known load response. No load/quiescent currents......Stator/down stream health check-up again
Maybe have a bad batt? Shorted cell perhpas, Batt/s running at 14'ish volts w light'ish known load/s, is this idle current at the rec measuring properly?
Just pondering idea's on the infant mortality rate ya have.......
