Diesel: water not coming out the exhaust?

[allanbranch]

About a week ago I replaced my johnson water pump on my yanmar 2GM20F motor...the kit was almost the same cost as a new pump, anyways.

Today I put it back on, hook-up the lines, start the motor and no water is coming out of the exhaust port. I see it blowing air on the water but no water. I stopped the motor and disconnected the water hose going into the motor and crank it. The pump is pumping water so I turn it off and hook it back up. I crank it again and start looking for leaks, nothing.

Where do I look next?
Could something be blocking the flow?

[Terra Nova]

Make sure the entire line to and including the riser raw water is completely clear, including the anti-siphon valve.

[roverhi]

Had the same problem. Check your though hull. Creatures can crawl in the inlet and block it. Close the valve/seacock and pull the hose. Open the valve and and run a rod through the fitting to clear out any little buggers that may be restricting flow.

[Sailmonkey]

Like terra nova suggests, check each section of the seawater path. But your clog is likely in the mixing elbow.

[Dave Lochner]

Check the gaskets on the raw water strainer. The old Groco strainers used cork, they dry out and leak air so the pump can not get properly primed.

[montenido]

This may sound silly, but have you tried reversing the hoses to the water pump? My last sailboat had a raw water pump that was easy to replace backwards, giving the same symptoms.


Cheers, Bill

[Cheechako]

So the pump is pumping water to the engine but it's not coming out the exhaust. Did your impellor fail originally? Is that why you replaced the pump? If so, you may have impellor pieces blocking the passageway somewhere.
Other options mentioned above: is water coming out where it connects to the exhaust mixer/elbow? Can you remove that hose and confirm?

[Mithril Bham]

All good suggestions above. Try 5 gallon bucket of water and put intake hose in the bucket and see if it works (with hose replacing water). That's how I run mine on the hard.

[Cheechako]

Roverhi, Dave Lochner and magellenyachts: He's already stated water comes out of the pump.... but doesn't come out the exhaust.

[roverhi]

Originally Posted by Cheechako

Roverhi, Dave Lochner and magellenyachts: He's already stated water comes out of the pump.... but doesn't come out the exhaust.

That may be true but the intake may still be restricted so that it won't allow enough water through to cool the engine. As others have said, check the entire system.

[boeing1]

I believe you said the raw water pump is pumping water, and when you remove hose on the output side of you pump you get water. if so suggest check your exhaust mixing elbow for being clogged,

[seabreez]

Originally Posted by montenido

This may sound silly, but have you tried reversing the hoses to the water pump? My last sailboat had a raw water pump that was easy to replace backwards, giving the same symptoms.


Cheers, Bill

I just rebuilt a pump for a friend and he wanted to install it himself. He had taken the precaution to mark the hoses and he installed the pump 180 degrees off and subsequently installed the hoses incorrectly. He switched them and voila!

[seabreez]

Originally Posted by allanbranch

About a week ago I replaced my johnson water pump on my yanmar 2GM20F motor...the kit was almost the same cost as a new pump, anyways.

Today I put it back on, hook-up the lines, start the motor and no water is coming out of the exhaust port. I see it blowing air on the water but no water. I stopped the motor and disconnected the water hose going into the motor and crank it. The pump is pumping water so I turn it off and hook it back up. I crank it again and start looking for leaks, nothing.

Where do I look next?
Could something be blocking the flow?

Is there a way to disconnect the hose going to your exhaust manifold and see if water is flowing? Is the motor mostly under the water level?

[beirutsailor]

May be much simpler. It takes time for the mixing elbow to fill up again. Wait a minute running the engine and water may miraculously reappear.

[sailorchic34]

It does take time to fill up the hoses and heat exchanger. Make sure the discharge elbow is not plugged. with the raw water hose off the discharge elbow you should feel a bit of exhaust coming out of the port with the engine running. if water comes out of the hose loose at the discharge elbow then the discharge elbow is clogged with minerals. That needs to be checked every 500 hours btw.