No water flow

Christo

Christo

Active Member
Feb 7, 2021
497
Michigan
Boat Info
2004 225 Weekender
Engines
Mercruiser 5.0 MPI/Bravo III Drive
Hi guys,

Went out to splash the boat yesterday and was disappointed:/ Got her in the water and started the engine, luckily I had the engine hatch open because I was looking for trim tab fluid leak. Realized quickly there was no water flow and shut it down. Ran perfect when I put it up last fall. This will sound stupid, but I think my marina didn’t unwinterize the boat. Is there any valve or something I need to open? Here’s a couple pics… B25FA5D2-5883-4C6A-9E87-4FE2FC8CDFB5.jpeg00AD32AE-B857-49BF-A2F8-CD31E18160C1.jpeg
 
Is your engine raw water cooled? Looks like a strainer basket?

If so, you need to open the seacock. Should be a valve with a handle on it.
 
It is a strainer basket, but there’s also a coolant reservoir, which confuses me. My manual references a seacock, but I cannot find where it’s located anywhere in the manual. Very frustrating.
 
Christo said:
It is a strainer basket, but there’s also a coolant reservoir, which confuses me. My manual references a seacock, but I cannot find where it’s located anywhere in the manual. Very frustrating.
Click to expand...


Coolant is raw water cooled via a heat exchanger. Follow the hoses from the strainer basket to the seacock (Im assuming there is one). I'm sure it's in the most impossible to see/use location buried deep down under/behind the engine.

Also, you could open the strainer and fill with water to get it primed.

One other issue is you might need a new raw water pump impeller if your ran it very long without water in it (they are cheap, and should be done periodically anyway).
 
It must be behind the engine, can’t really see back there, but there is an access panel on the back I can take off and look.
 
Oh good idea to fill the strainer with water.
 
You said "you" put it away last year... was it you or your marina?

You have a B3 so that means your raw water pump is belt driven. You also have a smaller boat so things should be very easy to find. Your manual may not be correct to what is ACTUALLY in your boat.

I also don't think that closed cooling was an option from the factory on that model? Nor does it look like a factory setup. That's not a big deal - but this just means that you have to do a little more investigative work on your own.

Follow the intake hose (from the strainer) backwards - your intake either comes from the hull bottom or the drive. Following that will show if you have a seacock or not.
 
My strainer baskets have drain holes on the side at the bottom. If that plug's not in, you could be sucking air, rather than water. That being said, my strainers are low enough that they're below the water line and water actually comes pouring in if those plugs are missing, but your strainer looks to be mounted up high enough that it might be above the water line.
 
Lazy Daze said:
You said "you" put it away last year... was it you or your marina?

You have a B3 so that means your raw water pump is belt driven. You also have a smaller boat so things should be very easy to find. Your manual may not be correct to what is ACTUALLY in your boat.

I also don't think that closed cooling was an option from the factory on that model? Nor does it look like a factory setup. That's not a big deal - but this just means that you have to do a little more investigative work on your own.

Follow the intake hose (from the strainer) backwards - your intake either comes from the hull bottom or the drive. Following that will show if you have a seacock or not.
Click to expand...
My marina winterized it…I’m not gonna be able to get back out there til Monday unfortunately:( but I will take the access panel off and follow that hose. Thanks for the input guys.
 
Christo said:
My marina winterized it…I’m not gonna be able to get back out there til Monday unfortunately:( but I will take the access panel off and follow that hose. Thanks for the input guys.
Click to expand...
If the input hose (at the strainer) is coming from the drive, it's directly behind the drive at the transom plate. I know those corner access plates only have 4 screws in them - but just look over top of the engine.

The assumption is that you should/would know if you had a thru-hull pickup and seacock... most likely you're getting water from the drive like normal. And whomever installed this aftermarket kit just plumbed the strainer inline on the way to the raw water pump.
 
Lazy Daze said:
You said "you" put it away last year... was it you or your marina?

You have a B3 so that means your raw water pump is belt driven. You also have a smaller boat so things should be very easy to find. Your manual may not be correct to what is ACTUALLY in your boat.

I also don't think that closed cooling was an option from the factory on that model? Nor does it look like a factory setup. That's not a big deal - but this just means that you have to do a little more investigative work on your own.

Follow the intake hose (from the strainer) backwards - your intake either comes from the hull bottom or the drive. Following that will show if you have a seacock or not.
Click to expand...

If he has a B3, might he also be suffering bravoitis?
 
If he does have a B3When was the last time you changed the raw water impeller? May be worth replacing if more than 2 years old!
 
Ok, so went out to the boat, no seacock (lol), the strainer hose was connected to the transom, very hard to see, so must be outdrive fed… put her in the water, topped off the water in the strainer, and still no water flow, got an overheat alarm this time… water pump? Impeller was replaced in 2021….any thoughts?
 
To get an overheat alarm it must have ran for a couple minutes? If that's true, whether or not the raw water pump was toast before... it most likely is now.
 
Agreed. Certainly the next place to start troubleshooting. Check for scoring in the brass plates of the impeller (if you have brass) and make sure you have all the vanes found from the old impleller as they can get elsewhre in the system if broken off!. If any scoring, Mercury does make a rebuild kit for most pumps. Worth a call and have your engine seriel number handy. Last if you you do not have a shut off from the B3 intake (strainer if you have one), this can be done in the water with a simple wood plug kit from West marine to fit your intake hose.
 
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