Flushing Impeller pieces

[cos_man99]

I have a 1996 Mercruiser 7.4 bravo 3. My raw water impeller disintegrated (long story). I have pulled apart the water pump and housing and located a number of impeller pieces in the hose that comes from the outdrive to the water pump (on the starboard side of the engine). I have not located any pieces in the oil cooler or thermostat housing. In counting the pieces I have found, I think there are still more pieces unaccounted for. My gut tells me they are all in that same hose which brings water from the lower unit up to the water pump. How do I get them out of there? The hose is currently disconnected from the water pump. Can I put muffs on the lower unit and run the garden hose full blast (obviously without running the engine) to force the pieces out of that hose into the bilge area? Is there another way? Thanks so much. Worried about wrecking my brand new impeller if I don't get the pieces out of there.

 

[thumpar]

I took the hose off the pump and put the garden hose in the hose where it would connect to thermostat. That backflushed that hose. I found all my pieces there.

 

[GA_Boater]

I took the hose off the pump and put the garden hose in the hose where it would connect to thermostat. That backflushed that hose. I found all my pieces there.

Yes - The chunks came from below and are easier to flush out in the reverse direction.

 

[cos_man99]

I did that same thing. No pieces came out from there. That hose was clear (from the water pump to the thermostat). The pieces I have found were in the hose that goes from the lower unit to the water pump. Interested in flushing that hose without sending all those pieces down into the lower unit. I could run a garden hose into that hose and backflush but I am not sure I want to do that. The pieces I did find were big enough they would not have come out the holes in the lower unit. So I am looking to flush in the same direction that water normally flows (up from the lower unit to out of the hose that is currently not connected to the waterpump). Do I dare try it with muffs and my garden hose on full blast? Is there anything that I could damage? Thanks.

 

[GA_Boater]

You should have back flushed while the drive was apart, but that ship has sailed.

If the disintegrating impeller clogged the water line up to the thermostat housing, there is a good chance of ending up with an impacted water supply line by using the muffs.

Run the boat and keep an eye on the temp gauge.

 

[cos_man99]

This is a bravo drive so the water pump/impeller is on the engine not in the drive. I have not taken the drive apart. I’m hoping to push the pieces out the top. I’m certain they are in the hose that goes from the drive to the impeller. All other locations are clear.

 

[thumpar]

It couldn't hurt anything. Just take the hose off the pump and run the muffs. You may have to hold them on tight to get water coming out the hose in the boat with any force.