Beta Marine 30 engine not passing enough seawater through the Raw water cooling

[ritchyp]

Hi,

During the weekend just passed, I decided to remove the heat exchanger on my Beta marine 30 engine and clean it out.
About 6 weeks ago we accidentally ran into a mud bank whilst tacking up Southampton water close to low tide. My yacht draws 1.8 m but with the fuel and both water tanks full and carrying tools, food and other equipment, plus crew, I call it 2.0m. We ran into a mud bank just before I tacked and got stuck for half an hour until the tide turned and we floated enough to reverse out . Whilst initially trying to reverse out under full power when we got stuck, I believe I sucked up a lot of mud and silt which caused a partial blockage in the raw water circulation. After that the engine always ran too hot but I saw the temperature warning light come on or have and the alarm beeper come on but it just smelled and felt to the touch like it was running too hot. There was water coming out of the exhaust but not as much as the manual says it should which is 2.0 L every 10 seconds. This I never measured but I never had a cooling problem before the incident. When I got back to the berth to leave for home, I took the cover off to turnoff the seacock and there was a big pool of rusty water in the engine bilge and the engine was very, very hot.

After flushing out the fresh water system and bleeding out the water until it ran clean. I drained it and refilled it with new coolant. It made no difference at all but at least the fresh water coolant was not rusty. I decided after reading the engine manual and getting an understanding of how the cooling system works, that the heat exchanger must be clogged up with mud and silt still so removed the rods and put then in a bucket of water with a strong de-scaler in it to soften any calcium deposits. This was all done successfully and on the back of the engine where the cap end has the anode and two pipe inlets/outlets. One of them was caked up with limescale so badly that opening was only about 6mm so we cleaned all that out until the bore of the outlet was restored back to its normal size.
It was all reassembled properly and a new anode fitted and yet more new coolant filled up to the maximum level. Before we started the engine, I filled up the raw water strainer with water so the impeller would not run dry initially but did not get any water out of the exhaust. Water was coming through the strainer so I thought it was purging the air and water would come through eventually and after a while it did but not enough and even as much as it was before we started. I decide to stop the engine and scour the manual for information but it said it was self bleeding so I started the engine and let it run for 5 minutes and the amount of water spitting from the exhaust seemed to be getting better so I thought that it was sorted and tidied up as we were going to go for a day sail on Sunday as the weather had improved and the boat needed a sea trial as I have fitted new instruments and transducers and had a lift out clean and antifoul. The last 6 weeks has been all work and no sailing.
It is worth mentioning a couple of things. Firstly, the boat was on the hard for 24 hours whilst we cleaned and antifouled her. The water from the raw water side of the cooling system must have drained out through the grill uptake on the bottom of the hull. When we were relaunched, they lowered us into the water stern end first to allow the raw water cooling system to fill up with water. It took a long time but eventually water started to come out of the exhaust so off we went to the berth briefly.
Secondly, after the aborted sea trial due to the alarm coming from the starter box and tacho. Later on that afternoon as we were packing to leave, my friend who was helping me to clean to the heat exchanger asked me for the manual which I gave him and he said I think I put the heat exchanger in upside down. I said do you mean the wrong around and he said no but 180 degrees the wrong way. It has alignment marks on it and on the engine so you get the rotation of it lined up correctly but looking at the diagram in the book, I believe I have re-fitted it 180 degrees out......? Then later on he said Actually I am not sure if it would go in upside down and if it went in without any resistance, and if the marks were lined up correctly, I don't think it would make any difference.

So after all that work and all the other work done over the last 6 weeks, I still have a boat that has a a fairly serious fault. Could the heat exchanger be the culprit or is there a way to purge the air locks (If there are any) I am stumped, we all are.

Anybody have any ideas please?

 

[morgandlm]

Possibly a stupid suggestion but have you removed and checked the raw water impeller? (you do not say that you did) I did a similar thing with my outboard and clogged it with mud after which I discovered the impellor had lost a couple of vanes. It would now be the first thing I would look at.

David Morgan

 

[oldharry]

... and if so, you need to find the vanes, as they will be somewhere in the system causing blockage. My raw water cooled Volvo sucked one up against the thermostat housing, for example.

 

[AntarcticPilot]

... and if so, you need to find the vanes, as they will be somewhere in the system causing blockage. My raw water cooled Volvo sucked one up against the thermostat housing, for example.

They can be guaranteed to be found in the last place you think to look. Also, it is VERY easy to be misled by checking the bits you've recovered; I thought I'd got them all and then discovered another two (in the last place referred to above!)

 

[VicS]

The tubestack must be fitted so that the marks line up but rotate it 180° and they will be correctly lined up again You cannot be 180° out as that will be correct again. There is no distinction between top and bottom



Take note of what has been said about the raw water pump impeller and check that out if you have not already done so.

Bearing in mind the scaling you found in the outlet from the HE I think the next thing to look at is the water injection into the exhaust outlet bend. This does not seem to be mentioned in the manual, not even in the troubleshooting section.

.

 

[Tranona]

your symptoms suggest inadequate seawater flow rather than freshwater coolant or blocked heat exchanger. Did you clean the grid on the seawater intake? they are really not necessary and can restrict flow if partially blocked. Next thing is check the strainer and that the hoses are secure and not letting air in, then the lid is airtight. Next the water pump itself. Physical check of the impeller and face plate. The system should be self priming up to the pump and you can remove the output hose from the heat exchanger to check you are getting good flow to there.

 

[oldharry]

Rereading I am increasingly inclined to suspect the raw water pump. As Tranona says, they are self priming, and should give a good flow within 10 seconds or so. if yours didnt then the problem lies in the raw water circulation.

 

[Sandy]

Like many above I'm scratching my head. Why did you work on the fresh water side and not the raw water side of the cooling system?

Start and the raw water sea cock and work through all the raw water hoses, pumps, interfaces and make sure that system is clear.

 

[ritchyp]

Nothing wrong with the impellor. Its one of the first things I checked. A new one was fitted just before I bought the boat but the previous owner kept the one he removed as it looked really good still. I checked it 6 weeks ago after the brief mud bank incident and I checked it again on Saturday to see if it still OK .

When the boat was stood on the hard for 24 hours I grill for the sea water uptake was blasted out with my Jet washer so all the solts in it were clean. I removed the seawater strainer just above the seacock for the seawater cooling inlet. That was removed and washed out to remove any foreign debris.

I was at the front of the engine when the heat exchanger was re-inserted and I heard the chap saying to a 3rd person those marks are all aligned now do you concur and he said "Just a smidge more clockwise bud, yeah that's spot on now" it was a couple of mm and then they said it was all aligned perfectly.

It was the next day when he asked me to look at the diagram in the manual and said I reckon Ive got it 180 degrees out. And then said I dont think it makes any difference as long as the arrows on the engine and heat exchanger are all aligned

I have checked all the obvious things.

Impellor looks fine and no ends missing.
Sea water inlet strainer checked and washed out and the lid screwed down tightly
The grating on the bottom of the hull where the water enters initially was jet washed out and no blockage there at all.

We are all mechanics (One of them more so on marine diesels) so I trusted them. I am pretty certain that the rubber seal was inserted correctly but I will have to check this myself now because I didn't see it with my own eyes.

There just isn't enough water coming out of the exhaust outlet on the stern of the yacht. I noted that the engine tone coming from the exhaust was to crisp sounding. It used to be more muffled by the water being expelled a the same time.

There seems to be just a small spray of a few droplets and then after an interval (too long!) a reasonable amount comes out but in between intervals, hardly anything at all.

My engine always starts fine without the need for any throttle. It fires up and starts in tick over but the alarm will keep beeping until you give it a slight rev. That stops the beeping. I figured it is a a warning start up test which is terminated when you rev the engine slightly. On Sunday, we had barely motored half a mile and the warning alarm started beeping what could cause that? There is an overheating light along the bottom of the engine start and tacho box but it was not lit so I wondered if it was a warning of low pressure on the raw water system.

One of the guys (who is more of an agricultural fitter) started moving the small plastic pipe that comes from the anti-syphon valve around. I was always going down into the hull bilge but he was saying it needs to be higher than the exhaust outlet. I think it is a breather or overflow pipe very small diameter.

I have to say, by this point I was feeling pretty fed up and irritated by the amount of time, work and money I have spent on the boat over the last 6 weeks and not been able to sail so I didn't pay any attention to the height of where he left it.
He called me today and said it could be a faulty thermostat and it said it may be an issue but it has got nothing to do with amount of sea water coming out of the exhaust or the lack of it but the 2 cooling systems are separate.


So it is self priming and self bleeding and as I said, I have checked all the obvious things. I have never had the warning beeper go off and we hadn't been running the engine for very long. I'm totally baffled!!

 

[penfold]

After all that work the only thing left unfettled in the seawater circuit is the exhaust elbow; I suppose some debris may be obstructing flow in there. I suppose the thermostat could have decided to fail coincidentally with the grounding, but that seems unlikely; easy enough to test, remove the thermostat and take it for an italian tune-up to see if the overheat condition reappears.

 

[ritchyp]

Like many above I'm scratching my head. Why did you work on the fresh water side and not the raw water side of the cooling system?

Start and the raw water sea cock and work through all the raw water hoses, pumps, interfaces and make sure that system is clear.

I wanted to clean out the rods because the engine is overheating and I thought they might be caked with lime scale. As it was, It was a very good idea because the on e of the inlet/outlets was completely caked up and the diameter was reduced from 20mm to 6 or 7mm so It was a good thing in one respect but raw water through put has got worse and now I have alarms going off.......:/

This may have occurred when the boat was stood on the hard and all the water drained out of the raw water system. I only ran the boat back to the mooring. The lad that jet washed the intake asked me if it was possible that he pushed some of the crud up into the pipe with the power of the jet washer. I said I don't think that is possible but I was not there when they did it as I was at the chandlers buying anodes for the prop and prop shaft

 

[ritchyp]

After all that work the only thing left unfettled in the seawater circuit is the exhaust elbow; I suppose some debris may be obstructing flow in there.

It just so happens that one of the mechanics that were with me was talking about it to his brother who has a qualification in marine engineering and worked on marine diesels for 8 years and he said the same thing. It is a very common place for blockages to occur there.....!

 

[wingcommander]

Its only self priming if their are no restrictions on its route back to sea . Ask me how I know. Mine refused to pump after a very roller downwind sail . Checked filter , found empty. So , Sea cock off , pour water in , filter lid back on , cock back open ,engine on and pumping again.
Checked everything from through hull to transom exhaust fitting.
Turned out to be second section of exhaust hose ( water lock outlet ) had been delamination and restricting the flow.
Photo of hose looking in a poor condition

 

[ianc1200]

I'm sure my answer won't be correct for your problem, but just in case....
Had my engine professionally serviced beginning of last season, including the heat exchanger being cleaned. Didn't start engine for about two months. When I did clearly not enough water coming out of the exhaust. Decided it was the oil cooler (2015 Beta 20 with PRM gearbox which has an oil cooler) and was indignant that hadn't been cleaned and looked at, but no real issue, only a minor amount of gunge in it . Guys on the pontoon said check the pipe taking the outlet from the raw water pump, but I had it off at the oil cooler junction and was completely clean. Checked pump, was ok but replaced the impellor anyway. Blew inflatable pump down the seacock pipe, decided that wasn't enough and went swimming under to check inlet. Tried taking the seacock pipe off and putting in a bucket of water. Started taking all the pipework apart, exhaust elbow, exhaust pipe, Took pipes leading to anti syphon device off and checked. By now was about 10 days in. People again said have you checked pipe over raw water pump. Did so and found it also completely blocked with limescale in rings like if you cut a tree trunk. Hard as anything but removed instantly with small screwdriver. Apologized to people who told me from the off to check that pipe. They did say it's where the water cools and limescale forms, and as others have suggested you need to follow the system through from sea cock to exhaust.

 

[scottie]

The route for water flow through the exchanger nest is best checked
the Volvo 2000 series engine uses seal bar or diverters which requires the whole thing To be correctly aligned

 

[Tranona]

I'm sure my answer won't be correct for your problem, but just in case....
Had my engine professionally serviced beginning of last season, including the heat exchanger being cleaned. Didn't start engine for about two months. When I did clearly not enough water coming out of the exhaust. Decided it was the oil cooler (2015 Beta 20 with PRM gearbox which has an oil cooler) and was indignant that hadn't been cleaned and looked at, but no real issue, only a minor amount of gunge in it . Guys on the pontoon said check the pipe taking the outlet from the raw water pump, but I had it off at the oil cooler junction and was completely clean. Checked pump, was ok but replaced the impellor anyway. Blew inflatable pump down the seacock pipe, decided that wasn't enough and went swimming under to check inlet. Tried taking the seacock pipe off and putting in a bucket of water. Started taking all the pipework apart, exhaust elbow, exhaust pipe, Took pipes leading to anti syphon device off and checked. By now was about 10 days in. People again said have you checked pipe over raw water pump. Did so and found it also completely blocked with limescale in rings like if you cut a tree trunk. Hard as anything but removed instantly with small screwdriver. Apologized to people who told me from the off to check that pipe. They did say it's where the water cools and limescale forms, and as others have suggested you need to follow the system through from sea cock to exhaust.

Agree. My guess is either the pipe from the seawater pump to the HE or possibly from the HE to the injection point - although from what he says there is an antisyphon in that line.

Anyway take the pipes off and clean them through. The one from the pump is long with bends in it so will need rodding from both ends.

 

[Birdseye]

They did say it's where the water cools and limescale forms, and as others have suggested you need to follow the system through from sea cock to exhaust.

One minor correction - from sea water inlet to exhaust. Likely you have a sail drive. Some Beta engines take their water from a hole in the saildrive leg and since you ran aground this may be part blocked. But ianc1200 is right. Follow the sythem through from sea water coming in to sea water being dumped from the exhaust.

Could be you have fried the engine and got a cylinder head gasket leak etc, but start with the simple things first. Dont get mechanical hypochondria and go for the complicated and expensive issues until all the silly minor ones have been checked out.

 

[Birdseye]

One minor correction - from sea water inlet to exhaust. Likely you have a sail drive. Some Beta engines take their water from a hole in the saildrive leg and since you ran aground this may be part blocked. But ianc1200 is right. Follow the sythem through from sea water coming in to sea water being dumped from the exhaust.

Could be you have fried the engine and got a cylinder head gasket leak etc, but start with the simple things first. Dont get mechanical hypochondria and go for the complicated and expensive issues until all the silly minor ones have been checked out. P.S. Got the T shirt on this approach

 

[VicS]

One minor correction - from sea water inlet to exhaust. Likely you have a sail drive. Some Beta engines take their water from a hole in the saildrive leg and since you ran aground this may be part blocked. But ianc1200 is right. Follow the sythem through from sea water coming in to sea water being dumped from the exhaust.

Could be you have fried the engine and got a cylinder head gasket leak etc, but start with the simple things first. Dont get mechanical hypochondria and go for the complicated and expensive issues until all the silly minor ones have been checked out.

the mention of seacock, strainer above it and particularly grill uptake on the bottom of the hull rather suggest otherwise.

.

 

[ritchyp]

Hi Birdseye,

It's a shaft drive, not sail. Prop is back in front of the rudder.

When we were on the hard a few weeks ago, there is a pair shaped grill. Mounted on the bottom of the hull about halfway between the back of the keel and where the propshaft emerges from the boat. That was blasted out with my jet washer and I could see all the gaps in it were free of debris and gunk.

So would I be correct in thinking that there is a hose somewhere in the bilge space that goes to the stop cock? The hose from the stop cock goes to the strainer and then the next goes from the strainer to the impeller pump if I'm correct.

We did remove the end of the hose that connects to the bottom of the impellor pump to drain out the sea water before removing the heat exchanger nest.

The thing that has confused me is that the engine was okay but I admit that it was running a little bit. That is why I cleaned the heat exchanger nest a d was going to put a new thermostat in also.

The sea water in the system drained out of the boat and most likely syphoned it all out via the intake on the hull and the exhaust outlet.
The lack of water flow did not present itself until I started the engine as we were being launched. Nothing came out for a quite a while and I was just about to kill the engine and then the water started to come out and got a little better but not as good as it has been before the lift out.

One of the posters on this thread said "It's only self priming if there aren't any restrictions"

I take that as I have airlocks in the system and because of unknown restricted flow, it can't purge the air out so it only spurts out when there is a build up of water pressure from time to time.

I have 2 marine engineers coming down in Friday as we were supposed to be sailing to Alderney this weekend but they are happy to help me fix the issue and go for an overnight sail down the coast somewhere.

Would it help to fill up the system via a hose pipe from the highest point, to at least fill the whole system with water again.

We are going to try and find this restricted flow obviously but if we still get this spitting and spurting after everything. Would filling the system up completely with water help get the water flowing again. Might even have to plug the exhaust out let with something.....