Friend has a 2005 Merc 150 outboard on a 19 Trophy CC. At 2000-2500 rpm temp gauge climbs to 200-240 within 5 min. Water shoots out of the hose and feels hot. Has steam showing at the back of motor. We never ran hot to get buzzer to sound. At other rpms temp is fine. New thermostats and pop valves. Water pump is new as well and installed correctly. These are trolling rpms so we are hurting. Any help would be great.
we just had a similar problem with a 60 hp four stroke only it was getting an alarm, there was a blockage in the water passage under the powerhead, one of the grommets was mis shaped causing the motor not to get enough water and overheat, pain in the you knowwhat to find and fix
2005 Merc outboard High Temp
