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Low raw water flow

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Alf572

New member
My mercruiser 7.4L with a bravo III outdrive is not pumping enough raw water to keep the engine cool. I have checked the impeller and it is in good condition. The hoses are all in good condition and I have not been able to detect any leaks. Does anyone have an idea as to where I should look next?
 
water goes in one side of the raw water pump you try removing the hose coming out the pump to see if you have good water comming out?

If yes move down the system say you have a heat exchanger? Water going in good comming out good? Keep moving down the system t-stat good opening?
 
There is a situation with Bravo`s on the water hose connection. Almost sure there was a bulletin on it. Corrosion builds up around the hose ends and causes them to collapse and restrict the water inlet flow.Where is your water inlet,from the drive or a thru-hull.
 
I didn't think of that one Bond-o reversed the hoses. Boat stays in the water mussels and living things clogging the inlet ?
 
Thanks for the responses. I did remove the hoses just after the heat exchangers and had low flow. There is enough flow to keep the pump from burning up but not enough to keep the engine cool. There is not enough suction to collapse the hose. I checked the hoses a couple of times to verify that they were connected properly. The intake is the top hose to the pump.The only thing left to do is to take the pump apart again to check for a blockage unless there are any other ideas out there.
 
Check the pump's output, aka do the flow test.

Did you lube the impeller vanes when you had the pump out? if not, you may need another one.
 
Just a follow up- I had a mechanic replace the transom assembly last year and then winterize the boat. i found the problem. Apparently they did not check to see that the water line through the transom assembly did twist when the put in the tapered insert. No offer from the mechanic to fix their mistake so now i am looking for a tapered insert extractor.
 
Alf572 said:
Just a follow up- I had a mechanic replace the transom assembly last year and then winterize the boat. i found the problem. Apparently they did not check to see that the water line through the transom assembly did twist when the put in the tapered insert. No offer from the mechanic to fix their mistake so now i am looking for a tapered insert extractor.
Click to expand...
WOW, He is willing to lose good potential customers for somthing that should only take him about one hour to fix his mistake.:eek:

It must be nice to busy in today's tough times.:rolleyes::D

The part number for the tool you are looking for to adjust that hose is (91-43579):)

http://www.marinepart***press.com:8080/mpeCart/details.faces?productId=91-43579

Good luck with it.
 
I have done a bravo transom assembly complete rebuild before.

I was shocked to see such a poor design for the pass thru connection.

The one I worked on the aluminum area on the outsdie diameter of the rubber hose had oxidized so badly that it had pinched the hose off by more than 50 %!!

Why they did not use a S shapped solid tube like the alpha's and coonect the hose with clamps on both side I will never understand.........
 
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