Sea water pump removal/reinstall

K

kevmacmills

New Member
Jun 15, 2010
12
Bellingham, WA
Boat Info
268 Sundancer 1989
Engines
7.4l Mercruiser, Bravo One
Greetings! I have a 1989 Sea Ray Sundancer 268 with a 7.4l Bravo engine and had a bit of a scare as I attempted to head out for a nice 3-day weekend: The housing of my sea water pump had developed a hairline crack and it failed! Water started filling the bilge and the alarm went off, letting me know my trip was going to be cut short. Happily, I wasn't too far away and made it back to the dock and got it out of the water.

The sea water pump on this engine is buried under the starboard side and the fuel filter/water separator is very much in the way. On my boat, the engine's fire extinguisher prevents access to the front of the pulley. Who designed this??

Anyway, does anyone have tips on how to get the pump out and back in? My Clymer's manual doesn't have a lot of detail and has no pictures of how to get it out and doesn't describe what to do about the belt - like how in the heck do you get it tight when you reassemble everything? "Reverse the removal procedure to reinstall the pump" isn't helping me much :)

Thanks for any pointers!
 
I usually remove the whole assy, brackets, fuel pump and all. then do everything on the bench.

Yours is different with the extinguisher oddly placed in the front (mine is on rear bulkhead), but it should come out easily. Don't forget to disconnect the 2 wires.
 
Well, I managed to get it out and I can say that the manual does not do it justice. The pump itself is mounted to a bracket that is essentially hanging on the block behind one of the cooling hoses. This bracket has 2 bolts and it comes out with the pump - you do not remove the pump from the bracket until it is out an on your bench. For the bolts, you want to remove the lower one and *only loosen* the upper one. You end up lifting the bracket up and off this top bolt, so you want it just loose enough. This top bolt is right behind a cooling hose so if you back it out too far, you won't have room to maneuver the bracket out between the bolt head and the hose. Lastly, there is yet another bracket arm that comes from the alternator that attaches to the bottom of the pump bracket. Really hard to get to that bolt! It is way down low and it has a nut on the other end, just in case you thought you wouldn't be fishing things out of the bilge.

So yeah, it came out but I'm really struggling to figure out how I'm going to get it back in since I have to keep tension on the belt. There is no idler pulley tensioner to help out here.
 
Tension on the belt should be adjustable not a spring-loaded tensioner but a teeth type tensioner on two round sprocket like gear things on the alternator maybe
 
kevmacmills said:
Well, I managed to get it out and I can say that the manual does not do it justice. The pump itself is mounted to a bracket that is essentially hanging on the block behind one of the cooling hoses. This bracket has 2 bolts and it comes out with the pump - you do not remove the pump from the bracket until it is out an on your bench. For the bolts, you want to remove the lower one and *only loosen* the upper one. You end up lifting the bracket up and off this top bolt, so you want it just loose enough. This top bolt is right behind a cooling hose so if you back it out too far, you won't have room to maneuver the bracket out between the bolt head and the hose. Lastly, there is yet another bracket arm that comes from the alternator that attaches to the bottom of the pump bracket. Really hard to get to that bolt! It is way down low and it has a nut on the other end, just in case you thought you wouldn't be fishing things out of the bilge.

So yeah, it came out but I'm really struggling to figure out how I'm going to get it back in since I have to keep tension on the belt. There is no idler pulley tensioner to help out here.
Click to expand...
Sounds about right as far as the removal goes. Pretty normal, actually, in regards to working on boats!

As far as putting it back on, yes reverse your procedure which should be pretty straight forward now that you did the removal. BUT... it seems like you're trying to install it with the belt attached? That's just insane to try and do that. Just install the belt once you're done and crank it tight with the tensioner.

Or... maybe you didn't look close enough on the removal and loosen the tensioner? As noted above, it's a very simple gear/sprocket that you slightly loosen then retighten after you get the right tension on the belt.

For future reference, a Mercruiser service manual will probably give you more detail.
 
Lazy Daze said:
BUT... it seems like you're trying to install it with the belt attached? That's just insane to try and do that. Just install the belt once you're done and crank it tight with the tensioner.

Or... maybe you didn't look close enough on the removal and loosen the tensioner? As noted above, it's a very simple gear/sprocket that you slightly loosen then retighten after you get the right tension on the belt.
Click to expand...

That's the problem - there is no tensioner on this belt. On the Bravo 7.4 (non Mag) the sea water pump belt goes directly to the main pulley.

Lazy Daze said:
For future reference, a Mercruiser service manual will probably give you more detail.
Click to expand...

I do have the service manual and it is frustratingly lacking in detail - hence my post :) I only discovered the fact that the bracket lifts off the top bolt by looking for the bracket part number online to find an actual photo of the part. The exploded diagram doesn't show the shape of the holes! Good fun...
 
upload_2023-7-31_4-16-0.png
 
There's always some kind of tensioning system. I think you're overlooking something. Look back (closer) at the notes we've written... and what Bill kindly posted... at 4am!

You mentioned you had a Clymer's manual... not a Merc manual as I suggested.
 
Hold the lock nut and move the adjustment bolt
 
I think mine is on the top right side. But it is the same system as described. I have changed my belt just last year
 
Yeah it's right above the power steering pump You loosen the center nut and then you can back it off with the smaller one or tension it with the smaller one then tighten the bigger one back up
 
kevmacmills said:
Thanks for the photos, but those are the pictures I found online and unfortunately don't match my boat. The 1989 Bravo One doesn't have an idler pulley next to the pump :-(
Click to expand...
If you don't have an idler pulley, then you'd physically move/adjust the bracket to adjust the tension. There is ALWAYS a way. Repeat... there is always a way. Look closer :)
 
Lastly, there is yet another bracket arm that comes from the alternator that attaches to the bottom of the pump bracket. Really hard to get to that bolt! It is way down low and it has a nut on the other end,





This is the tensioner. ^^^^^^^^^^^


If you would take the bracket off on the port side near the alt instead of struggle like you did----You will find a slot on the other end of this bracket near the alternator.
 
kevmacmills said:
Greetings! I have a 1989 Sea Ray Sundancer 268 with a 7.4l Bravo engine and had a bit of a scare as I attempted to head out for a nice 3-day weekend: The housing of my sea water pump had developed a hairline crack and it failed! Water started filling the bilge and the alarm went off, letting me know my trip was going to be cut short. Happily, I wasn't too far away and made it back to the dock and got it out of the water.

The sea water pump on this engine is buried under the starboard side and the fuel filter/water separator is very much in the way. On my boat, the engine's fire extinguisher prevents access to the front of the pulley. Who designed this??

Anyway, does anyone have tips on how to get the pump out and back in? My Clymer's manual doesn't have a lot of detail and has no pictures of how to get it out and doesn't describe what to do about the belt - like how in the heck do you get it tight when you reassemble everything? "Reverse the removal procedure to reinstall the pump" isn't helping me much :)

Thanks for any pointers!
Click to expand...
Take a picture of your setup, and/or share the serial number of your engine (if you didn't already). In 1989, illustrators were drawing the diagrams, and not so much using CAD technology. We were barely figuring out how to get away from Microfiche. As an aside, I replaced my seawater pumps with a pump that uses a bolt on pulley instead of a press on. That way, I can remove the pully, remove the bolts to the pump, slide it backwards, and then under the bracket to service or remove it for bench servicing.
 
ASH said:
Lastly, there is yet another bracket arm that comes from the alternator that attaches to the bottom of the pump bracket. Really hard to get to that bolt! It is way down low and it has a nut on the other end,

This is the tensioner. ^^^^^^^^^^^

If you would take the bracket off on the port side near the alt instead of struggle like you did----You will find a slot on the other end of this bracket near the alternator.
Click to expand...

This is the key - thank you! There is indeed a bracket, completely hidden from view, that attaches to the bottom of the pump and goes all the way under the engine and up to the alternator. The replacement part finally arrived and I'll be tackling it in the morning before it gets too hot.

Now... for the replacement body: There are 2 seams inside where each port is carved out. These feel awfully sharp - not something I'd want the impeller rubbing against, I think? Shall I sand those down or are they part of the design?
 
Well, it's in! Took about 2 hours of fiddling to get it all buttoned up, but that's 2 hours I didn't pay a shop rate :)
For anyone who attempts this, please check out this thread regarding torque specs:
https://www.clubsearay.com/index.php?threads/seawater-pump-cover-torque-specs.73260/
My manual was wrong, listing 30 ft-lb for all the fasteners, which is like twice what it should be. May very well be why it cracked!
 
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