Hot Water

[Seriously]

Quick update 

well the thermostatic valve was found  in the housing . We then tested it in boiling water with the new valve both worked but the newer one reacted quicker. So my mind at peace for the moment and we did not sheer the bolts off getting the plate off.

So if the thermostatic valve are working now  I think it points to the temp sender . Maybe it's the wrong one as both thermo valves have 82 degrees written on them. Engine temp should be getting up at least 82  on gauge. 

so I will fit the new sender within the next couple of weeks . 

Does any body know where the coolant is added to the engine.  We had the water pump off a couple of weeks ago   trying to find the thermostatic valve , I  need top up it up for the winter. We think in the header tank on top of engine is that correct ? 

 

 

[Seriously]

We also learnt something new between the three of us this weekend . I was explaing to my friends that it spins they both said no it can't do , as the shape of the housing does not allow it . But as we all found out at the weekend it does 

[BroadAmbition]

Yes it does spin otherwise no flow will occur, all the impeller is, is a basic pump at the end of the day. 

Topping up the cooling system - best use some coolant, not just plain water. Header tank / heat exchanger will have a spring radiator cap on it to allow you to remove it and top the system up, DON'T do this unless the engine is cold

Griff

[Seriously]

Hi Griff

 that what we thought but you never know Thanks

[Vaughan]

That raw water pump impellor is "shot", and you must replace it. One blade is about to fall off and another two are cracked. I can also see that the rear face plate is worn, and so the front plate will be as well. Can you show us a photo of the inside face of the front plate?

Both of these plates are easily removed and can be turned, to give them a new length of life.

To take out the impellor take a couple of medium/small screwdrivers, one on each side of the impellor central body, and lever it gently off the shaft. Doesn't matter if you hurt the rubber as it is shot anyway. Next remove the cam. on the right side of the pump in your photo is one screw, which holds the cam in place. Be careful not to lose these screws as they are a special thread and must only be replaced with genuine Jabsco parts. After this, a bit of gentle prodding with a screwdriver and the back plate will fall out in your hand.

You simply have to turn it over, make sure the face is smooth with light sanding or a fine flat file, and put it back in again, new face facing front. Then put the cam back.

Smear the pump body and the new impellor liberally with grease and then replace the impeller with a clockwise turning motion so that the blades against the cam are flattened in the correct direction.

File the original outside face of the front plate to remove paint, and any little protrusions around the screw holes, then fit the gasket with plenty of grease on both sides, followed by the front plate with the "new" face inwards - also well greased. This will give you several more years out of the pump.

In winter, take the impellor out when you drain the raw water system and leave it on top of the engine, to remind you that you have removed it. Some people leave them in a bowl of water. If you don't remove it then the blades which stay squashed against the cam all winter will go hard and next time you start, they will crack, and soon snap off. This is what happened in your case and it is probably the reason why your engine has overheated in the past.

By the way, if you buy a new sender and it shows you that your engine is running normally, that still doesn't tell us why you are not getting hot water for showers.

Have fun. Or alternately, call Mark from MBA, as someone needs to check that the pump body and the cam are not also worn, and I can't do that from here!

[tjg1677]

Agree with everything that Vaughan says above. Done loads of these and that looks like it is about to self destruct.

Just two additional tips - smear the drive shaft splines with grease too. secondly, I always used to get a good finished surface on the backplate and cover plate by rubbing on a thick piece of plate glass using fine grinding paste, gives a far better and more even finish.

trev

[Vaughan]

There are three purposes for the grease :

To lubricate the rubber and keep it soft.

To make a joint that will not let air in.

To provide "suction" for the pump so that it will start to draw water and thus prime the pump when cold starting.

 

If when starting up, you find you have to run the engine fast, before water comes through, then your pump is worn and needs attention.

I put suction in inverted commas as there is no such thing as suction, but never mind that for now!

[Seriously]

Hi to all

Thanks for your input

So you are quite right I have still not found out what the issue is with the hot water. As your said earlier the engine not running correctly is or was more important. So in bite sizes I'm slowly knocking issues of the list of things that could be causing it . Also my brain deals with things in  bite sizes a lot better  .

My memory is shocking so looking back maybe the hot water has always, not  been  brilliant. So in the end, I think mark suggestion,  it might be the tank is knackered.I would have said its the original tank But working through each issue is giving me knowledge and fun  . At some point I will be upgrading the tank with a emersion heater in it to help when I arrive at the boat yard on a Friday night . Also traveling around the broads at low revs and for less than two hrs cant help my hot water but does help Norfolk

Sorry for the drift

So yes you are correct the impeller housing front plate has signs of wear ,probably  the only thing that I did take a picture of

Quote

If when starting up, you find you have to run the engine fast, before water comes through, then your pump is worn and needs attention.

How would you know ? can I assume you undo the  clip and take the hose off and see how much water comes out ? Also when your boat is winterised is it a standard common practice for them  to take the impeller out of the  pump ? leaving it on show.

 

[Vaughan]

Basic principle, as taught on all trial runs :

Start the engine, and before casting off the lines, check to see you have water coming out of the exhaust. If not rev the engine up in neutral and watch. If still no water, stop engine and phone boatyard. You can also hear a dry exhaust. If it is making a noise like a motor bike then stop the engine.

 

It depends how you winterise your engine. Some yards run anti-freeze through the raw water system before stopping the engine for the last time, but this is not very green!

Normally you drain off the raw water side and have antifreeze in the internal side. Some hire yards change their impellors every spring anyway, so they are not bothered. I always remove the impellor during draining and leave it aside to "relax" during the winter. That way, on a private boat, you will get several years out of it.

[Seriously]

Looks like at some point they have used the front plate around the other way   and then swapped it back around . 

[Vaughan]

Ye Gods.

At least you can still read the part number, to order a new one!

 

[BroadScot]

Any money in scrap brass? Just a thought! 

Iain

[MBA Marine]

5 hours ago, Seriously said:

Looks like at some point they have used the front plate around the other way   and then swapped it back around . 

I see plenty so badly worn on both sides that not only has the writing gone but the brass is paper thin in the middle, people do like to get their monies worth.

[Seriously]

Mark exactly what I was thinking at least another twenty years left in that baby 

[Vaughan]

Well you don't need our help then.  

[Seriously]

5 hours ago, Vaughan said:

Well you don't need our help then.  

sorry Vaughan hope I have not offended you regarding my above post. I was just joking. I always need help. as I'm  learning new things all the time. I'm just a tight git .

[Vaughan]

1 hour ago, Seriously said:

sorry Vaughan hope I have not offended you regarding my above post. I was just joking. I always need help. as I'm  learning new things all the time. I'm just a tight git .

I am sorry as well - maybe I am a grumpy git, sometimes.

Trouble is, you have faced us with a mystery, here. The Perkins MC42 has a much smaller raw water pump than other engines such as the Nanni, the BMC 1.5 or the Perky 4108. Your pump is actually the same one that was fitted to the old Ford Watermota. We have always wondered why this is, but have assumed it is because it is a long reach, low revving  engine.

When you started this thread it had seemed that the engine was running too cool and we have been trying to work out why. Now you show us photos of the raw water pump, which is - how to put this? - buggered. It has also clearly been bodged by a previous owner. That pump can only be running at half its capacity, if that, and yet the engine is too cool?

Have you followed Mark's advice and checked to see whether the heat exchanger actually has a tube stack in it?

I have tried to help but I am 1000 miles away. You need a genuine Broads mechanic to come and look at it, and get his hands on it. Only then, will you know what is wrong.

[Seriously]

Morning

Thanks for your help and your  input. Yes a mystery it is . The pump looks to me that it has been on a while and my boat being a ex hire fleet I would hope it has been running ok like this  for years with no problems. A big assumption i know . Except for  the impeller and cover plate that  needs sorting out which is wear and tear , which I'm on with . Yes you are correct i need a marine engineer to come and have a look . Which will happen, but as you well know they are not cheap. So I'm just knocking off the jobs i can do myself  and learning stuff on the way. Which will help in the future if any thing goes wrong. So i can have a understanding of any new  problems that arise. Then i will call in the professionals.
Very confusing tho as the data says it should run at 82 Degrees  but i have read it is a colder engine so running 50 Degrees is ok. Information on the mc42 is limited and this is why you are correct i need someone to have a look at it . As for checking the stack in the heat exchange , its on my radar.

You have not tried to help you have helped. So hopeful by the end of the year hopeful we will have this sorted and  the answer posted on here  for any body in the future looking at this post.

 

[Hockham Admiral]

On 03/06/2016 at 0:34 PM, Mowjo said:

Another point that someone like Mark may or may not confirm is that the Red ignition light forms part of the charging circuit, if it's not working or the bulb has blown the battery's won't charge,,

You are quite correct. Here it is in black and white!

" Field current supply is provided from two different sources - from the alternator itself, via the diode trio, and from the battery, via the alternator warning lamp. When you first get in the car and turn the key on, the engine is not running and the alternator is not spinning. At this time, the voltage/current source for the field current is from the battery, through the ignition switch, and through the warning lamp. After the engine is started, and the alternator is up to speed, the output of the diode trio is fed back to the regulator, and serves as a source of current for the field current. At this time, the alternator is self sustaining, and the battery is no longer needed to power the electrical system" 

[Matt]

I have been reading this thread with interest but have only just put 2 and 2 together!

Thunder has an MC42 and if memory serves me correctly runs along at 80-85 degrees at mostly 1800-2000 revs.

 

[tjg1677]

Still think the hot domestic water problem, which is what this thread was all about originally, is down to the calorifier being the wrong way up or plumbed in incorrectly.

 

[MBA Marine]

5 hours ago, tjg1677 said:

Still think the hot domestic water problem, which is what this thread was all about originally, is down to the calorifier being the wrong way up or plumbed in incorrectly.

 

If you want a pair eyes to look at your system,  or someone to advise and chat over a coffee, I would be happy to.  I have a £30 minimum charge with a £20 per hour labour rate.  I cannot magic the solution, you are working your way through most things that I would look at, but if you want an assist you may not have to mortgage your home. 

[Seriously]

Hi Mark

Sounds like a date I will  give you call  . I am up last in the week in October  for a week ,so would be good if you could fit me in .

Karl

 

[BroadAmbition]

Could it be something as simple as the tank need bleeding?  There is bleed key on the back end of our Vetus water tank, it is easily missed

Griff

[Seriously]

Hi All

update

A big thank you to Mark for your help . Would highly recommend mark to  any one who needs any help with their boat full of knowledge and very helpful.

Mark will hopefully be along soon and give a better  update and a more technical update.

Engine temp gauge and sender seem to be working ok. Mark stripped out the heat exchange stack only problem was that the inspection panel in the engine dept. was not big enough . so we could not get it out completely but what we could see was ok. So my next job will be to make the access panel bigger . I will then take it our inspect and clean it..

We took the impeller out and turned off the sea cocks and ran the engine for as long as we could but could not get the engine above 50 Degrees . Which is strange as the thermostatic valve  will only kick in at 82 degress so in practice the thermostatic  value never opens as the engine never gets above 50 Degrees.

So next thing to try to stop the water from the hot water system circulating as this could be cooling the engine down. I did think about slightly turning the sea cocks to slow the raw water down which is also cooling the engine down . So still a mystery

 

Karl