Seawater not pumping

[LittleSister]

Started an indirect cooled Beta engine for the first time in a long time. Engine started fine but the seawater side is not pumping (temporarily inlet hose into bucket as boat is ashore).

Impeller is intact and wet and rotating. Heat exchanger is full ( enough) of coolant. I’ve tried revving engine, in case that might get it going, but this just results in exhaust blowing back through seawater pipework (which suggests to me problem is not blockage).

I’m a bit flummoxed. This should be easy and I maybe I am having a senior moment and missing the blindingly obvious.

Any ideas?

 

[jwilson]

You don't have a rag stuffed up your exhaust do you?

 

[Blue Seas]

Started an indirect cooled Beta engine for the first time in a long time. Engine started fine but the seawater side is not pumping (temporarily inlet hose into bucket as boat is ashore).

Impeller is intact and wet and rotating. Heat exchanger is full ( enough) of coolant. I’ve tried revving engine, in case that might get it going, but this just results in exhaust blowing back through seawater pipework (which suggests to me problem is not blockage).

I’m a bit flummoxed. This should be easy and I maybe I am having a senior moment and missing the blindingly obvious.

Any ideas?

Quick, cheap checks,
1. Bucket not too low for water pump suction?
2. Air leak on suction side?
3. Could try priming suction side?
4. As said, exhaust blockage.

 

[LittleSister]

Thanks both.

I think it is fixed if not actually ‘solved’. I put the inlet pipe back on the Vetus inlet strainer, filled that with water (through-hull closed), and it drained continuously at various revs.

The bucket I was previously using was below that, but only about 6” or so below the seawater pump, and probably about or even above sea level when the boat is afloat.

A bit challenging to do further investigation now as I am alone and the Vetus strainer (needing constantly adjusted filling), and engine controls ( and exhaust outlet are all in different locations.

No rag or other blockage in exhaust, don’t think the inlet hose is leaking, I had primed it as best I could by turning inlet hose to point upwards and filling with water when I first started engine

 

[chriscallender]

Is the inside of the cover plate on the pump worn at all? Often that makes them difficult to prime and get going. As a (semi ) temporary solution or something to try you can usually just turn the cover over with the engraving on the inside and the screw holes still line up.

 

[oldmanofthehills]

Is the inside of the cover plate on the pump worn at all? Often that makes them difficult to prime and get going. As a (semi ) temporary solution or something to try you can usually just turn the cover over with the engraving on the inside and the screw holes still line up.

I had that issue with a johnson pumped volvo penta. Did flip over as a temp fix but changed engine soon after as other issues

 

[srm]

Helping a friend with a boat he chartered. he always checked everything so opened the Vetus strainer. Engine started with cooling water in exhaust. just outside marina breakwater exhaust note changed - no cooling water so stopped engine. He had created an airlock in the strainer. Shut seacock filled strainer to top, opened seacock and started engine - problem solved.

 

[PeterV]

When my Beta 20 stopped pumping water last year both ends of the metal water pipe from the pump to the heat exchanger were blocked with scale. Nowhere else, just those two little spots.

 

[Poignard]

Is the lid of the Vetus strainer sealing properly?

 

[ChromeDome]

Thanks both.

I think it is fixed if not actually ‘solved’. I put the inlet pipe back on the Vetus inlet strainer, filled that with water (through-hull closed), and it drained continuously at various revs.

The bucket I was previously using was below that, but only about 6” or so below the seawater pump, and probably about or even above sea level when the boat is afloat.

A bit challenging to do further investigation now as I am alone and the Vetus strainer (needing constantly adjusted filling), and engine controls ( and exhaust outlet are all in different locations.

No rag or other blockage in exhaust, don’t think the inlet hose is leaking, I had primed it as best I could by turning inlet hose to point upwards and filling with water when I first started engine

What strainer?
I have them with the flat clear lid and made a copy from Plexi. Fitted a garden hose connector to it and now can keep the tap open as the strainer will fill, engine will suck and excess water is going out via the seacock.


Another way is to connect the water supply hose to the impeller pump intake [hose]. This will push water into the pump so hoses will be under pressure while the impeller is at standstill.

 

[srm]

What strainer?

Sorry my mistake.
I thought an earlier post referred to the Vetus large strainer that is usually mounted level with the boat's static waterline. The top is clear and can be opened for cleaning should there be a blockage. As @Poignard suggests any leakage around the O ring will break the suction and prevent water flow.

 

[LittleSister]

What strainer?
I have them with the flat clear lid and made a copy from Plexi. Fitted a garden hose connector to it and now can keep the tap open as the strainer will fill, engine will suck and excess water is going out via the seacock.


Another way is to connect the water supply hose to the impeller pump intake [hose]. This will push water into the pump so hoses will be under pressure while the impeller is at standstill.

Yes, I'm trying to concoct something like that, without it turning into a project in its own right and distracting from the jobs I was actually setting out to do!