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Raw water not pumping

mibix

By mibix
in Boat Building & Maintenance

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mibix Explorer

mibix

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Hello.

 

I had my engine on today charging up the batteries, and it started chugging. I noticed it wasn't pumping any water out! I have a feeling that some weeds have gotten their way into the system and wanted to ask a quick couple of questions.

 

is this the stop cock and water pump?

Do I just turn the knob anti-clockwise to close it?

If I turn it the wrong way and disconnect the pump, do I have time to turn it the other way before my boat sinks?

Do I then remove the pump and have a look if there is any blockages or a damaged impeller?

 

Sorry for all the questions, don't want to end up sinking her!

 

p7BnaAK.jpg

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Tony Brooks Veteran II

Tony BrooksDonate to Canal World

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It is the stop (sea) cock but I think the bit on top is a weed stainer. The raw water pump is normally engine driven. Occasionally by a belt (BMC 1.5 - some) or more usually a brass pump mounted directly on the engine.

 

Any loose connection or air leak between the sea inlet and pump will reduce or stop water flow, as will a damaged impeller in the pump or a worn pump.

 

It looks like a grp hull and if so usually the raw water pump is above the water line so can be dismantled without turning the seacock off.

 

The seacock turns off just like any other gate valve but I can not remember which way. Someone else will be along soon to tell you. Has anyone turned it off for wintering afloat?

 

There are rarer things like a blockage in the exhaust or bits of muck/impeller wings caught in hoses or heat exchanger cores that can cause loss of raw water but make sure the cock is turned on and check the suction side and pump before worrying about anything else.

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Flyboy Experienced

Flyboy

Posted
Posted

Hello.

 

I had my engine on today charging up the batteries, and it started chugging. I noticed it wasn't pumping any water out! I have a feeling that some weeds have gotten their way into the system and wanted to ask a quick couple of questions.

 

is this the stop cock and water pump?

Do I just turn the knob anti-clockwise to close it?

If I turn it the wrong way and disconnect the pump, do I have time to turn it the other way before my boat sinks?

Do I then remove the pump and have a look if there is any blockages or a damaged impeller?

 

Sorry for all the questions, don't want to end up sinking her!

 

p7BnaAK.jpg

It would be normal to turn the valve clockwise to close it, the same as a tap.

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mibix Explorer

mibix

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Great thanks. The water pump looks to be belt driven. A pipe comes from this weed strainer to the engine pump. If weeds are stuck in the strainer, can that stop the flow? Is it worth checking this before dismantling the water pump? I noticed the water pump does drip when the engines running.

 

It wasn't winterised. We lived aboard it over winter, so the stop cock is open. It sounds like it's trying to pump water but nothing is coming out.

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Puddlejumper Collaborator

Puddlejumper

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If the water flow has stopped and the engine was running for more than a few Min's the pump impeller is probably goosed as well better to check any signs of cracks slink it and fit new. Stop cock clockwise to shut anti clockwise to open then turn back a 1/4 turn stops it seizing up better still when next out on dry land fit a ball valve instead saves having the gate seizing if left in one position for along time the can on top of the tap is a weed trap

 

 

edit If the impeller has any broken vanes make certain to remove them from the pipework as they can get in them in extreme cases

Edited by Puddlejumper
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mibix Explorer

mibix

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Thanks puddlejumper. It's getting too dark to do anything tonight, but getting to the impeller involves removing the pump and dismantling? And take the old impeller to a shop to show and get a new one (and gaskets)?

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Naughty Cal Veteran II

Naughty Cal

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It would be normal to turn the valve clockwise to close it, the same as a tap.

Not always!

 

Some of ours turn clockwise, some the other way!

 

We were told that if it's facing the same way as the outlet pipe it's open if it's at 90 degrees I e barring the flow it's shut. Which is simple enough.

 

If you are struggling with raw water flow check the impellor. 99.9% of the time that's what is wrong with ours.

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Puddlejumper Collaborator

Puddlejumper

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Thanks puddlejumper. It's getting too dark to do anything tonight, but getting to the impeller involves removing the pump and dismantling? And take the old impeller to a shop to show and get a new one (and gaskets)?

 

I would personaly get 2 kits so you have spare onboard when out and about ( Sods Law states if its goin to go again you will be miles away and stuck)clapping.gif

Not always!

 

Some of ours turn clockwise, some the other way!

 

We were told that if it's facing the same way as the outlet pipe it's open if it's at 90 degrees I e barring the flow it's shut. Which is simple enough.

 

If you are struggling with raw water flow check the impellor. 99.9% of the time that's what is wrong with ours.

NC sounds like you have ball valves on your boat

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Naughty Cal Veteran II

Naughty Cal

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Not sure but when we had to take the raw water pump off to replace the seals we left her afloat via a Tesco plastic bag!

 

Probably not a great idea. Had the bag dislodged she would have made her way to the bottom of the lake!

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BEngo Veteran II

BEngoDonate to Canal World

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If its a jabsco type pump take out the 4 or 6 small screws that hold the front plate of the pump on and remove the plate. you can then pull the impeller out with a pair of long-nosed pliers. If it's missing any vanes you need to find them before they cause a problem. The important numbers which describe the pump are on the front plate and that is what you need to take to the shop ( jabsco/ITT have an excellent on-line shop IME) and ask for a new impeller for one of these please. If the impeller is well banjaxed there won't be any vanmes so the shop will have little to compare it with.

 

Since the pump drips you will also need a new gasket for the front plate and probably the rear seal if it's dripping at the back. Dismantling is pretty self evident.

 

When refitting twist the impeller into the hole in the direction of rotation ( shown on the front plate)

 

NC- OP has a gate valve, not a ball valve like yours. Gate valves are like a tap, usually.

 

N

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Brin Morris Collaborator

Brin Morris

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I had a similar set up on my first boat. when I had the problem of low water flow I checked the weed filter and it looked clear so I removed the impeller and it was ok. The cause was a bag was partially blocking the inlet at bottom of boat. I would check weed filter if that is clear leave filter out and open the sea cock to make sure you have a good flow(open it slowley and you can close it in plenty of time before boat would sink). If you have a good flow go to impeller. If you do not have a good flow I used to rod out from filter to bottom of boat with a bottle cleaning brush. You have to be quick and ready to close off the tap when the blockage clears.

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mibix Explorer

mibix

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Hi guys,

 

I've decided to buy a new impeller and gasket etc. for the pump. Before pulling it apart, I tried to ID it, but there are no markings on it. Is it just the stock one that came with the engine? The engine is a Yanmar YSE12L. Is that what I need to look for?

 

O3mFqVR.jpg

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Naughty Cal Veteran II

Naughty Cal

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Yeah it's a bit soggy - the water pump leaks when running, and the bilge pump has decided to konk out. Hopefully a new gasket for the pump will stop the leak.

 

You might find it needs a new seal kit.

 

Thats what we had to replace on ours. Not a difficult job, on the VP pump anyway.

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mibix Explorer

mibix

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You might find it needs a new seal kit.

 

Thats what we had to replace on ours. Not a difficult job, on the VP pump anyway.

Cool I'll have a scout around the internet see if I can get a whole new everything for it!
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OldGoat Veteran II

OldGoatDonate to Canal World

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Hi guys,

 

I've decided to buy a new impeller and gasket etc. for the pump. Before pulling it apart, I tried to ID it, but there are no markings on it. Is it just the stock one that came with the engine? The engine is a Yanmar YSE12L. Is that what I need to look for?

 

O3mFqVR.jpg

 

 

Something about the shape of the pump makes me think it could be a Jabsco??

 

They do make quite a number of pumps and were (?) leader until Johnson came along. There aren't than many manufacturers....

 

Jabsco illustrated spares here:-

 

http://www.jabscoshop.com/marine/pumps/bronze-engine-cooling-pumps/

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