Overheating - Low water Pressure

[tmfarrell]

I was getting low water pressure on my 5.0L Mercruiser Bravo III engine and it was starting to overheat. I assumed it was the impellers on the seawater pump. I replaced those today and starated the engine to find out I still had the probelm. Water seemed to be getting to the distribution housing but it wasn't getting to the thermostat housing unit. I belive the seawater pump was working correctly but I wasn't getting any reading on the water pressure.

Did I replace the impellers wrong or could it be the thermostat?

Thanks

 

[Ididntdoit]

I was getting low water pressure on my 5.0L Mercruiser Bravo III engine and it was starting to overheat. I assumed it was the impellers on the seawater pump. I replaced those today and starated the engine to find out I still had the probelm. Water seemed to be getting to the distribution housing but it wasn't getting to the thermostat housing unit. I belive the seawater pump was working correctly but I wasn't getting any reading on the water pressure.

Did I replace the impellers wrong or could it be the thermostat?

Thanks

I would bet on a restriction somewhere before the raw water pump - drive intakes/drive passages/or small transfer hose from the drive to the bell housing Is the boat wet slipped in salt water? When was the last time the drive was off and the cases split?

 

[tmfarrell]

Thanks - I removed the hoses on the outlet side of the pump to the sensor and made sure they were clear - no obvious obstructions. But I also checked the flow from the pump - ran for 15 seconds and got about a gallon of water. From what I can tell that is normal. I then hooked everything back up and ran the boat watching the temp and water pressure. Ran for about 10-15 minutes and the temp stayed steady at 159-160. Water pressure stayed at .1-.3 psi. I think the sensor might be faulty or clogged and temostat might be sticking also. Going to replace both and see what I get.

 

[shore]

I had the dreaded transom clog.I had to put a thru-hull water pick up in to fix it.Worlds of difference in waterflow.