As some of you know i had new long engine fitted last year,so today i picked up a new boat.No problems towing until i got to a long incline noticed a few puffs of black smoke from exhaust and temp went up to 3/4 mark ?? any ideas what could cause it.

tia

Check your radiator isn't blocked, mine raised to three quarters whilst towing up a hill and turned out to be a blockage. Puff of black smoke....check fuel filter , throw some injector cleaner in it , and check no air pipes are split