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Water circulation problem.


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4 minutes ago, marji said:

.......... every once in a while I would give it a few wipes with my deck broom and carry on

Just to repeat, reinforce, what Tony is saying, when you have raw-water (river / canal / sea) cooling then it is imperative that checking and cleaning the inlet filter is one of the jobs on your pre-start up check list.

 

EVERY time before starting the engine it should be checked.

 

If the water is badly affected by weed you should be checking the exhaust flow every 'few' minutes, and if there is no-flow then stop the engine. even 5 minutes without water can destroy the impellor.

Just a belt and braces job, but I carry both spare impellors and a complete spare pump, it is sometimes easier to replace the pump than try and replace the impellor in situ, you can then 'service' the pump at your leisure.

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2 minutes ago, Alan de Enfield said:

Just to repeat, reinforce, what Tony is saying, when you have raw-water (river / canal / sea) cooling then it is imperative that checking and cleaning the inlet filter is one of the jobs on your pre-start up check list.

 

EVERY time before starting the engine it should be checked.

 

If the water is badly affected by weed you should be checking the exhaust flow every 'few' minutes, and if there is no-flow then stop the engine. even 5 minutes without water can destroy the impellor.

Just a belt and braces job, but I carry both spare impellors and a complete spare pump, it is sometimes easier to replace the pump than try and replace the impellor in situ, you can then 'service' the pump at your leisure.

I am up for buying a pump and replace it then service the old pump, have you any idea of where and what pump to order, or best wait until I get more detailed photos?

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1 minute ago, marji said:

I am up for buying a pump and replace it then service the old pump, have you any idea of where and what pump to order, or best wait until I get more detailed photos?

Tony is the expert on BMC engines and has worked on them for years, but there are often variations depending on who & how they were marinised, so I'd suggest first see which one you have then get a replacement.

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52 minutes ago, Mad Harold said:

I used brass wire mesh rolled into a tube shape,and inserted into the seacock.

The mesh is available on e bay and is used mainly in model making.It comes in various densities,and if I remember correctly,I used the type with 2mm spacing gaps.

On some days it did block frequently,depending on how "weedy"the canal was.

I made the strainer inspection part of my pre-cruising checks,and had no trouble with blockages.

It was simply a matter of unscrewing the cap on the seacock,pulling the strainer out and swishing it in the canal.

 

 

That is exactly what I would hope the OP has but it seems not. I don't like those plastic Vetus type things, especially when mounted above the waterline.  Eventually they get very difficult to seal from  air leaks.

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1 hour ago, marji said:

I am up for buying a pump and replace it then service the old pump, have you any idea of where and what pump to order, or best wait until I get more detailed photos?

 

PLEASE don't throw money at this. Lest do proper diagnosis so you  spend as little as possible for the optimum result. Have you seen the  cost of new pumps !!!!!!!

 

Still assuming your pump is the one I think it may be then wear takes place in three places.

 

1. In the body where the shaft passes through it without any discrete bearings. You test for this by trying to see how much play there is between shaft and pump body. If you can see the movement then it is probably worn. I think your pump probably has two grease caps on it and if these are not turned regularly the body will wear.

 

2. This type of pump has a gland nut like a mini-stern gland where the shaft exits the body. The packing inside wears and allows air to be drawn into the pump rather than water. Even with a worn pump body repacking the gland often allows it to prime for a short while.

 

3. This applies to all impeller type pumps. The back plate wears so the impeller can no longer form an airtight seal. On many pumps this can be "cured" by simply turning the end cover over but I suspect in your case the end plate my also contain a "nose" to support the back of the shaft so it can't be turned over.

 

More advice if you want it when we get to see the pump.

 

The Thorneycroft 108 and the BMC 1.8 are both the same thing. In your case the engine was marinised by Thorneycroft. If Calcutt had marinised it it would have been a Calcutt 1.8 and the engine parts (as opposed to marinisation parts) woudl be the same on both engines so for the purpose of obtaining spares etc it best to call it a BMC 1.8.

Edited by Tony Brooks
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27 minutes ago, Tony Brooks said:

PLEASE don't throw money at this. Lest do proper diagnosis so you  spend as little as possible for the optimum result. Have you seen the  cost of new pumps !!!!!!!

Mine are engine driven and they are £450 inc VAT each.

 

 

Marji - this is what the impellor should look like. If run dry the 'lumps' on the end of the vanes burn off / break off and will get sucked into the cooling system

 

The other problem with this type of pump is that if it is not used regularly it can 'dry-out' and the 'lumps' weld themselves to the pump housing, when you start the engine for the first time after 3 or 4 months they are totally 'welded'.

When leaving the boat for a long time the impellors should be removed.

 

Note the direction of 'bend' of the vanes - when reinstalling the impellor ensure the go back in the correct 'way' or the vanes will be snapped off on the first rotation

 

The pump cover should have the direction of rotation marked on it.

 

 

 

b1.jpg

 

Edited by Alan de Enfield
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From your picture your boat looks to be a Norman 22 mk3.Quite old,but nothing wrong with that as the older boats were usually made with thicker fibreglass than more modern computer designed hulls.

I had pretty much the same problems with engine cooling as you,on my last boat,and advice from Tony and others helped solve them.

You will like me learn how to solve boaty problems quickly,with the help of this forum.

I do think that buying a boat is rather like taking up with a new woman,in that you don't really know her untill you have lived with her for a year.

Please keep us informed how you are getting on.

Best of luck.

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Tony I have the gasket and will soon be going to the boat, I have made up two scoops to remove the water oil mix under engine to get better photos and I have printed two of your longer posts so I can read while I am on the boat and in some of the cases act on.

 

Alan I have one of them it was on the boat when I bought it, only problem is it will be in my shed, hopefully.

 

Harold I won't walk away from this thread I will make sure it is updated so anyone in the future can reference it, also I want to get more knowledge of my boat so will stick around after it gets fixed.

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1 minute ago, marji said:

Tony I have the gasket and will soon be going to the boat, I have made up two scoops to remove the water oil mix under engine to get better photos and I have printed two of your longer posts so I can read while I am on the boat and in some of the cases act on.

 

Alan I have one of them it was on the boat when I bought it, only problem is it will be in my shed, hopefully.

 

Harold I won't walk away from this thread I will make sure it is updated so anyone in the future can reference it, also I want to get more knowledge of my boat so will stick around after it gets fixed.

When you get over the present problems have a study of the notes on my website, they were written for ordinary folk.

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7 hours ago, Tracy D'arth said:

As Tony said, the pump impeller will be ruined because it has run dry. All the bits will be in the heat exchanger tubes and the hoses, you will need to get them ALL out otherwise it will block up again.

TD'

I did mention earlier in the post that all the impeller would have failed due to running dry and the vanes will need to be removed from the pipework Things just seem to get repeated, and we go around in circles.

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11 minutes ago, Steve56 said:

I did mention earlier in the post that all the impeller would have failed due to running dry and the vanes will need to be removed from the pipework Things just seem to get repeated, and we go around in circles.

Yes, strange how folks come and post the same thing 32 posts later.

 

I'm sure you noted that I posted it in post #8 and you then repeated the same in post #40 14 hours later

 

 

Post #8

Assuming you do have an impellor pump, if you have been running the engine dry(no water flow) it is quite possible that you have 'burnt' the vanes off the impellor, so even when the filter is clean it will no longer pump. You will need to strip the pump down and extract the impellor, ensuring you get all of the little bits of rubber out (as they can block pipes) and fit an new impellor

 

Post #40

If you have run the engine and have not had water coming from the exhaust then the chances are the impeller has disintegrated. The will not last long running dry. Any blockage in the inlet can cause this. Also if the impeller has failed you should try and retrieve any broken vanes from the internal pipework as they can cause restricted flow.

 

 

Let he who is without sin cast the 1st stone.

Edited by Alan de Enfield
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3 minutes ago, Alan de Enfield said:

Yes, strange how folks come and post the same thing 32 posts later.

 

I'm sure you noted that I posted it in post #8 and you then repeated the same in post #40 14 hours later

 

 

Post #8

Assuming you do have an impellor pump, if you have been running the engine dry(no water flow) it is quite possible that you have 'burnt' the vanes off the impellor, so even when the filter is clean it will no longer pump. You will need to strip the pump down and extract the impellor, ensuring you get all of the little bits of rubber out (as they can block pipes) and fit an new impellor

 

Post #40

If you have run the engine and have not had water coming from the exhaust then the chances are the impeller has disintegrated. The will not last long running dry. Any blockage in the inlet can cause this. Also if the impeller has failed you should try and retrieve any broken vanes from the internal pipework as they can cause restricted flow.

 

 

Let he who is without sin cast the 1st stone.

But has the OP checked it?

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14 minutes ago, Alan de Enfield said:

Yes, strange how folks come and post the same thing 32 posts later.

 

I'm sure you noted that I posted it in post #8 and you then repeated the same in post #40 14 hours later

 

 

Post #8

Assuming you do have an impellor pump, if you have been running the engine dry(no water flow) it is quite possible that you have 'burnt' the vanes off the impellor, so even when the filter is clean it will no longer pump. You will need to strip the pump down and extract the impellor, ensuring you get all of the little bits of rubber out (as they can block pipes) and fit an new impellor

 

Post #40

If you have run the engine and have not had water coming from the exhaust then the chances are the impeller has disintegrated. The will not last long running dry. Any blockage in the inlet can cause this. Also if the impeller has failed you should try and retrieve any broken vanes from the internal pipework as they can cause restricted flow.

 

 

Let he who is without sin cast the 1st stone.

In total agreement but the OP has not till the later post acknowledged that the pump will require attention. Just covering the bases guys.

TD'

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9 minutes ago, Tracy D'arth said:

In total agreement but the OP has not till the later post acknowledged that the pump will require attention. Just covering the bases guys.

TD'

 

 

We all are but some are picking at individual items and some are trying to understand the problem and produce a fix that solves all the problems not just one of them. Its a dead cert that if it did not prime in 10 minutes of running a new impeller is not going to solve it on its own.

 

it should not be a willy waving competition to see who can get an answer first. Usually it requires a combination of peoples' inputs to effect a cure.

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I have just got back and have loads of photos and videos, I will upload them and link to youtube the videos, I am going to try put them in some order and things changed as I progressed, for example I might say I can't get this off and then in another video I got it off.

 

I will upload in stages to try keep some order so part one will be when I arrived and I will show you the water filter for interest, all videos will be numbered as a reference.

 

I have done more then I thought I could have done, and it is all down to all of you who have replied in this thread, it might not have looked like I paid attention but I took it all in.

 

Ok roast dinner time, then I will add media.

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You already know those holes are way too big on that filter, so I won't point it out again...

 

oops...

5 minutes ago, marji said:

A question the two brass caps are they supposed to be fully tightened or tightened over time to push grease in to the pump?

The latter.  Tony B did mention it in one of his posts. 

 

Remove that cover plate with the 5(?) screws and you'll see the impeller.

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5 minutes ago, WotEver said:

You already know those holes are way too big on that filter, so I won't point it out again...

 

oops...

It worked for 4 years nothing got in, the algae surrounds it and acts like a membrane only reason I now have this problem is after 4 years the metal bolt I used to connect the flask to the pipe corroded and this is why I have this problem now, all happened during the last move I made 4 weeks ago, I did not notice no filter was on the pipe until after I had moved.

Edited by marji
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37 minutes ago, marji said:

It worked for 4 years nothing got in, the algae surrounds it and acts like a membrane only reason I now have this problem is after 4 years the metal bolt I used to connect the flask to the pipe corroded and this is why I have this problem now, all happened during the last move I made 4 weeks ago, I did not notice no filter was on the pipe until after I had moved.

That filter is an absolute gem of inventiveness and should go into the forum archives of DIY greatness.

 

However it is not really suitable and should be replaced by a properly designed (and sized) filter.

How does the pipe go thru the back of the boat ? (can you do a picture of it going thru from the outside and also another (taken from the inside) as it comes inside.

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Video of rear water flushing 

 

 

 

Video outside boat checking flow

 

 

8 minutes ago, Alan de Enfield said:

That filter is an absolute gem of inventiveness and should go into the forum archives of DIY greatness.

 

However it is not really suitable and should be replaced by a properly designed (and sized) filter.

How does the pipe go thru the back of the boat ? (can you do a picture of it going thru from the outside and also another (taken from the inside) as it comes inside.

I am willing to buy a filter I just can't seem to find one.

 

and yes I have a pic of the inside hose.

 

 

hose inside.jpeg

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