Went to put the new impellor on and the old one is in pieces. I get that I need to backflush the system... do I pull the hoses from the bottom of the manifold and stick the garden hose in there???? or someplace else??

The trick is to back flush each cooler., the broken impeller pices get caught in the coolers. If you can try and save the pices and match up with old impeller, this way you will know if you got them all.

Are these the coolers your talking about?? I have 2 of them on after the other.


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Start with the heat exchanger closest to the seapump, and match the parts to the impellor. They may be in the large oil cooler on the bellhousing.

there is no large oil cooler on the bellhousing. There are a total of 3 coolers, 2 along the side of the oil pan and one on the front of the motor. All in line one after the other from the seapump to the themostat deal,

If you can get enough pressure on the hose that goes into the bottom of the thermostat housing you may be able to blow all the pieces out in one shot. It is not hard to use a little PVC fitting and a hose connector to make a flusher. Otherwise remove each inlet hose from each cooler and pressure up the outlet and collect what comes out in a rag.

Hi Folks! Just to verify, is it correct that this is where i should jam in the hose on each side of the motor to back flush? (well thats what i did last weekend, although i didnt see anything come out of the hose which usually clamps to the outflow side of the water pump)



Thinking about it further, i suppose that i should also block off the hose on the frontside of the motor which goes to the opposite side of the block (where the stream splits to flow to both sides) so that all pressure is pushing material back towards the water pump, would that be correct? (see photo below)

Am i on the right track here?
Thanks for the advice!

Just follow the hose from the sea water pump to the first cooler (most likely power steering) pull the hose off both sides and flush through the cooler, you may have to use a tie-wrap to dislodge some pieces. Big rubber pieces wont get past the first cooler.

Ok i'll have to take another look. I tried tracing where the hose out of the pump leads to but it couldn't tell with absolute certainty (hard to see under the block)... although It seemed to me that it ran next to a fitting on the very back of the block near the transom. Is there any reason why its not just as good if I'm pushing the water from further down the line? Reduced pressure perhaps?