4sure
Member
Gentlemen
Can you please advise me concerning a cooling system on my 1999 Sea Ray 27’ Sundancer with a raw water cooled Mercruiser 454, Bravo III drive. Last season when at cruising speed, about 3300 RPM the engine temp was a constant 165 degrees. No engine work was performed over the winter other than winter storage processes as advised in the 454 Mercruiser service book. When the boat was put in the water, there was an overheat condition which was diagnosed as an obstruction in the hose from the drive to the raw water pump. The hose was cleared, the water pump flow test was performed and the overheat condition was gone. During the process of troubleshooting the overheat condition the thermostat, a large water hose (leaking) and the water pump impeller were changed, all Mercruiser parts. The exhaust manifold, risers and water pump housing were inspected and looked fine (the old water pump impeller was good, it was change anyway).
Now at cruising speed, 3300 RPM the engine temp is almost 180 degrees, the port riser is at 112 degrees and the starboard riser is 200 degrees. The heat gun shows 165 at the thermostat housing. On the warmer riser, the water hose going from the thermostat housing to the bottom of the exhaust manifold is significantly warmer that the port side.
There are no water temp measurements in the service book. Are these temps a normal condition? Would you suggest any other testing I can do?
Can you please advise me concerning a cooling system on my 1999 Sea Ray 27’ Sundancer with a raw water cooled Mercruiser 454, Bravo III drive. Last season when at cruising speed, about 3300 RPM the engine temp was a constant 165 degrees. No engine work was performed over the winter other than winter storage processes as advised in the 454 Mercruiser service book. When the boat was put in the water, there was an overheat condition which was diagnosed as an obstruction in the hose from the drive to the raw water pump. The hose was cleared, the water pump flow test was performed and the overheat condition was gone. During the process of troubleshooting the overheat condition the thermostat, a large water hose (leaking) and the water pump impeller were changed, all Mercruiser parts. The exhaust manifold, risers and water pump housing were inspected and looked fine (the old water pump impeller was good, it was change anyway).
Now at cruising speed, 3300 RPM the engine temp is almost 180 degrees, the port riser is at 112 degrees and the starboard riser is 200 degrees. The heat gun shows 165 at the thermostat housing. On the warmer riser, the water hose going from the thermostat housing to the bottom of the exhaust manifold is significantly warmer that the port side.
There are no water temp measurements in the service book. Are these temps a normal condition? Would you suggest any other testing I can do?
