sea water pump woes

D

dieselsmoke

Member
Aug 21, 2016
95
nj
Boat Info
2004 Select 220
Engines
5.0mpi bravo
At the end of last season I wanted to change the impeller on my bravo 3. I took the the pump off the motor and disassembled it. The casing was scored so I purchased a kit with plates and shorter impeller to rebuild it. I reassembled it and put the boat away for winter. Today I started it up and found the smartcraft gauges reading only .2 pound water psi on the muffs. The risers were getting hot so I shut it down. I took the hose off the power steering cooler that comes from the sea water pump and started it back up. The discharge from the sea water pump with the engine running was barely a burp and I could smell the winter antifreeze still in the system after running for a minute or two. So I assume that the pump is not working or I have a blockage between the drive and the upper input hose on the pump. I just had the drive off and inspected it and all looked good so I dont believe I have a blockage. I also back flushed the supply side with the garden hose and water flowed out of the drive immediately. Can I assume that removing the discharge pump at the power steering cooler and finding barely any water coming out points to the pump??? Thanks guys!
 
I only have inboards so forgive me if this doesn't work on yours.

When you removed the old impeller were all the rubber veins still there? Did you or even can you back flush the system?
 
Top hose is intake. Bottom is discharge out to power steering cooler correct??
 
Just the opposite on mine, but mine has the older style pump.

You probably want to look into that to be sure
 
dwna1a said:
I only have inboards so forgive me if this doesn't work on yours.

When you removed the old impeller were all the rubber veins still there? Did you or even can you back flush the system?
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One of the veins was missing and I found it in the cooler. I was able to back flush the supply side and found it to be clear The pump isnt picking up a prime for one reason or another I believe
 
You also said you used a different impeller and rebuilt the pump. When you did that you put in a new wear plate.

A smaller impeller would not compress against the wear plate, moving less water. Also it could allow the water in the pump to be pulled out. Also when you rebuilt the shaft bearing moved freely with no binding?

I have a feeling the issue is with the impeller. I know it's a pain in the butt but I think I'd pull it out and put the pump manufactures impeller back into the pump.
 
dwna1a said:
You also said you used a different impeller and rebuilt the pump. When you did that you put in a new wear plate.

A smaller impeller would not compress against the wear plate, moving less water. Also it could allow the water in the pump to be pulled out. Also when you rebuilt the shaft bearing moved freely with no binding?

I have a feeling the issue is with the impeller. I know it's a pain in the butt but I think I'd pull it out and put the pump manufactures impeller back into the pump.
Click to expand...
When I rebuilt the pump I put the wear plates in it which forced me to use a shorter impeller. I purchased a complete rebuild kit. The manufactures impellar will not fit unless I remove the wear plates and that brings me back to a scored bronze housing
 
IF there are no blockages on the intake side, keep in mind we have different systems, and no blocks on the output side it leaves you with the pump. Forgive the questions, I know the pump just not your system,

Does that style motor have a strainer and or a Seacock? A blocked strainer basket or a Seacock that looks to be open but has failed to fully open will give you low intake.

Hoses, how old are they? Sometimes the old hoses collapse on the inside, my Port side did that.

Is the pump one of those that has a plastic head side or totally Bronze, also what caused the scoring? The bronze style can be completely rebuilt with new bearings and seals. Even with a new wear plate you still use the same size impeller. The Jabsco pumps are easy to rebuild as long as the shaft is still true and the housing has not been damaged by bearing failure
 
I just had this issue and it turned out to be the cork gasket on the strainer cap missing a small piece of it, enough to have the pump sucking air instead of water. Of course it was found AFTER taking apart the pump and checking the impeller.
 

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dwna1a said:
IF there are no blockages on the intake side, keep in mind we have different systems, and no blocks on the output side it leaves you with the pump. Forgive the questions, I know the pump just not your system,

Does that style motor have a strainer and or a Seacock? A blocked strainer basket or a Seacock that looks to be open but has failed to fully open will give you low intake.

Hoses, how old are they? Sometimes the old hoses collapse on the inside, my Port side did that.

Is the pump one of those that has a plastic head side or totally Bronze, also what caused the scoring? The bronze style can be completely rebuilt with new bearings and seals. Even with a new wear plate you still use the same size impeller. The Jabsco pumps are easy to rebuild as long as the shaft is still true and the housing has not been damaged by bearing failure
Click to expand...
There is no strainer or sea cock, The intake side of the pump goes to a fitting on the transom that then goes and attaches to the bravo 3 drive. The hoses appear to be fine and Im guessing it was changed once already because it is a red hose while everything else is black. The pump is totally bronze and I assume the scoring came from sand being sucked into the system and then churned around in the housing. Im going to replace the pump and keep my fingers crossed!!
 
Don't throw the old pump away.

Let's us know how it turns out please
 
It may still be the original hose. That red hose is the inlet from the outdrive. It is extra thick so as to prevent it from collapsing.

That’s how it comes from the factory.

On my 2007, the red inlet and black pump outlet hoses are different diameters, it’s not possible to hook them up backwards.
 
Espos4 said:
It may still be the original hose. That red hose is the inlet from the outdrive. It is extra thick so as to prevent it from collapsing.

That’s how it comes from the factory.

On my 2007, the red inlet and black pump outlet hoses are different diameters, it’s not possible to hook them up backwards.
Click to expand...
Good to know. Thank you
 
New sea water pump solved my problem. Can anyone tell me what is the appropriate water psi at idle on muffs. I ask so i know if my gauge is accurate since i know the pump is working properly. I had a reading of .7 at idle on muffs. Is that about right? Thanks guys
 
And keep the Rpm very low while on muffs.

For me it’s idle Speed only.

There simply isn’t enough water volume from the garden hose for higher rpm operation without risking impeller damage.
 
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