Impeller problem? I hope!

E

EdFitz

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Went to help a friend de-winterize his Mercruiser 5.7 Mag with a Bravo III. It was winterized in the fall, all lubes changed, block drained of all water, but no anti freeze added.

It started right up on the ear muffs, but there was a squeeking sound, as if the serpentine belt was loose. After a few minutes of trying to detect where the noise was coming from, the belt stopped moving altogether. We shut it down immediately, and I removed the belt from each of the pulleys to determine that the water pump was very difficult to move by hand. All aother components (power steering pump, alternator, tensioning pulleys) spun freely.

Is it possible that the impeller has been destroyed, and is jamming the pump, or is it more likely that the pump itself is bad?
 
Ed,
those Bravo seawater pumps are hard to prime after a long winters nap. Try disconnecting the inlet hose and put the garden hose right in there to fill it with water. when you put the muffs on you have to make sure it's good and tight otherwise the water just blows out all over the place but none goes into the drive.
Rob
 
I would think it's the bearings going out (or gone) in the water pump... Once the seal goes, water gets into the bearing and it's downhill from there. Eventually it will seize.

But for starters I'd follow Capt Bill's advice (open it up).
 
I just redid mine this weekend and installed it this morning. Before you open it, use a little white paint to make a stripe on the two halves and on the mounting bracket so that you can align all three pieces when you put it back together. Remove the nuts and lock washers which hold the bracket before you try to remove the bolts.When apart, try to turn the pulley without the impeller attached. If it turns easily, your problem is not the pump; check the idler pulley. You'll have to refurbish the pump anyway - new O-rings and impeller. A little vaseline on the inside of the pump makes it easier to slide the inpeller in. Wrapping the impeller in a large plastic tie which you can tighten as you bent the vanes into place also makes it easier to put the whole thing together, When assembling, catch one bolt and then slide the housing halves around to catch a second bolt. The rest is easy. I added a second set of hose clamps to the hoses. Imagine, the most impostand set of hoses in the boat held with single clamps! Hy
 
i had the bearing seize on my crusader's pump, after the smoke cleared i replaced the whole unit
 
The same thing happened to my inboard a few years ago. They share the same kind of pump. Boatfix sells a repair kit that includes the impeller and gaskets (Mercruiser 47-59362T 6). You will need a new housing too because the old one will be scored. Don't try to use it because it will burn out the new impeller real fast. If I recall, the housing kit also includes a new impeller and gaskets too. Sorry, I didn't keep that number.

ps. I got curious and looked up the part number. It's probably Merc 46-807151A14 and it does include the impeller, wear plate, and new bolts too.
 
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