No water passing thru engine ??? Mercuiser Bravo III

This is a recent problem, just notice today. I have been maintaining, getting boat ready to sell for moms estate.

This is a 5.7 XL BravoIII Mercruiser, ............ I have been running the boat often in the driveway, water has always passsed thru the engine and out of the exhaust port where the outdrive connects to the hull.

Today there was no water passing thru the engine and exiting as usual. The temperature went up fairly quickly, I shut the engine off when the temp reached 170 or 180.

The belts are all in place, and the water pump isn't making any unusual noise's that I would expect from a water pump for a car engine........ Hum !!!

Totally at a loss here, ................ anyone have any ideas, thanks.

Re: No water passing thru engine ??? Mercuiser Bravo III

Ayuh,... It probably needs a new raw waterpump Impeller,...

Re: No water passing thru engine ??? Mercuiser Bravo III

Are you refering to the "water pump" on the front of the engine or an impeller inside the outdrive ???

Re: No water passing thru engine ??? Mercuiser Bravo III

I just had the same problem. Depending on your set up mine was a sea water impeller went bad (front of engine). You need to make sure you get all the rubber pieces out I just hooked up a shop vac and sucked them out. it actually worked pretty good. hope this helps

Re: No water passing thru engine ??? Mercuiser Bravo III

Are you refering to the "water pump" on the front of the engine or an impeller inside the outdrive ???

Click to expand...

Ayuh,... Bravos don't have 1 In the drive,..
It's motor mounted, but it's Not the 1 that looks like a Car waterpump...

Re: No water passing thru engine ??? Mercuiser Bravo III

Ok, now I'm getting somewhere, ............. the sea water pickup pump is located (looking at engine form the front) down at the lower left corner of the engine block. Service Manual 17, Book 2 of 2, Sections 5 thru 9, page 6A-15.

This isn't going to be easy to get at, yet not as difficult as other parts on the engine.

There is a Seawater Pickup Pump Output Test on page 6A-6, and it states this test can "Only" be performed in the water, and This test CANNOT BE performed with a flush-test device and water hose. ......... Hum ???

I wonder if I even need to do this test when no water is comiong out of the engine.

Re: No water passing thru engine ??? Mercuiser Bravo III

I wonder if I even need to do this test when no water is comiong out of the engine.

Click to expand...

Nope,... Not really,... You need to pull the complete pump,+ replace the Impeller,...
It's a pretty standard part of Servicing a boat...
It's a Much Easier job with the pump on the Bench, rather than in the Bilge....
Btw,...
Pay very Close attention to which hose goes Where....

Re: No water passing thru engine ??? Mercuiser Bravo III

Yes, my thoughts exactly, if the engine were out of the bilge it would be really easy.

Reached under and grabbed/felt where the hose's are connected for the clamps just to see if I could do this, or if I'd rather send it to the shop, lol.

I don't know why they don't use Serpentine Belts instead of multiple belts, hum. I don't even see a "Pivot" point for tightening the belt, I'll keep looking, I'm sure it has to be there.

My thinking is if I can losen the pump and swing it to a slack position I'll be better able to reach the hoses.