Steam in Exhaust D2-40

[Scorcher IV]

Hi,
I have a Bav 37 Cruiser with a D2-40 engine and it emits steam when over 1500 revs, not a huge amount but enough to concern me. I have replaced the exhaust elbow, cleaned the heat exchanger, replaced the air filter, had the injectors serviced, changed the impeller but still it steams. Water flow would seem to be the problem but I cannot find out just how much should come out. The engine starts and runs well, but I am still concerned. Has anyone had a similar problem and did they solve it or put up with it. Is fitting another water intake the answer and if so where?
Simon

[PEA-JAY]

I had a similar prob on my boat. Mine has a D2-55. In the end I found that the problem was a blockage in the sail drive. Marine growth to blame. While on the hard I cleaned the intake out as best as possible from the sail drive end after which I plugged all inlet holes and flooded the sail drive with white vinegar. I repeated this twice. It takes one litre. I left the vinegar do its work overnight each time. This dissolved all the remaining marine growth. I also had a tiny leak on the suction side of the raw water filter. I cleaned and lubricated the seal and now I have no air bubbles in the inlet pipe. Steam problem finally solved! Hope this info helps.

[Scorcher IV]

Pea-Jay,
I have a clear inlet pipe and there is a constant small stream of small bubbles in it, what did you lubricate the seal with? and the advice re the white vinegar will be carried out when I bring the boat out of the water in June. I have wondered if it was marine growth in the sail drive.

[Symphony]

Sounds like you have air getting in the seawater circuit. Common causes are hose clamps not tight enough or the cap of the water strainer not seating properly. There is no air below the waterline so it must be coming in after the seacock on the saildrive.

If there is no sign of overheating of the engine there is clearly enough water flowing to keep the fresh water cool enough so no harm to the engine, but probably little margin before it is not enough.

[PEA-JAY]

I use Hylomar Greasil 4000 o-ring lubricant, very handy to keep a small tube on board. When you service the filter remove the seal and clean it carefully. When reassembling make sure that the strainer is properly seated as I noticed that if I was not careful it sort of fitted slightly sideways and probably this is why air leaked into the system. I also found that lubricating the lid's coarse thread helps to screw it in place much easier and seals better too.

[Salty]

Hi,
I have. . . . . . .  cleaned the heat exchanger, . . . . but still it steams. Water flow would seem to be the problem. . . . . Has anyone had a similar problem and (how) did they solve it.
Simon

You mentioned that you had cleaned the heat exchanger, but did you actually remove the tube nest from the manifold, and importantly did you check that there were no obstructions within the pipework from the raw water pump to the inlet to the manifold heat exchanger?
After buying my B36 secondhand, I too had steam coming from the exhaust. This was caused partly by broken off impeller vanes from the time that the previous owner had the boat and mussel shells that had got around the pretty useless water filter that is fitted. Together these had reduced the flow of water by about eighty percent. Cleaning the water channel within the saildrive is now an annual task, and you can get a "bottle brush" to help with this. You need one with a small overall diameter but with very stiff bristles as those mussels must have learnt a trick or two from the Klingons.

[JEN-et-ROSS]

We use a wire coathanger with the 'hook' cut off and the remaining two 'corkscrew/helical' wires carefully unwound. The 'hanger was then straightened.
 One of the resulting two corkscrew-like ends is just the right diameter to be inserted right up the lower intake of the saildrive and used to persuade the incumbent molluscs therein to relinquish their tenancy, it's quite a shock how many there are in there each year. Not surprising that their presence can restrict the water flow.  (Reminds me of Corporal Jones and his famous catch-phrase !! )

[dawntreader]

Whilst out on a walk some years ago I found a 500mm long 13mm hammer drill bit on the roadside. This has been ideal for inserting into the bottom hole of the water intake in the saildrive and manually turning to remove the debris. Also, make sure you back-flush the system to remove loose pieces once you've done the cleaning job

[PEA-JAY]

The water passage inside my 130S-A sail drive does not go in a straight line towards the inlet ball valve but there seems to be some internal chamber and the passage is offset. I tried poking both from the drive end as well as the top by removing the ball valve using all sorts of pieces of cloths hanger, screw drivers, piano wire but didn't manage to find a passage from the top to the bottom which is why I resorted to vinegar to dissolve the encrustations. I'm curious to learn if anyone manage to poke the sail drive right through.

[JEN-et-ROSS]

PEA-JAY. Our Saildrive is a 120. The passage is straight from the bottom to the top, BUT, the ballvalve is on the Port side of the gearbox base so unless the water passage IS angled slightly inside the saildrive leg, then we also have an, albeit very short, inaccessible section.

[Brian]

Are you certain it's steam and not unburnt diesel, I had a similar problem with my D2-55 which was solved by servicing the injectors.

[JEN-et-ROSS]

Are you certain it's steam and not unburnt diesel, I had a similar problem with my D2-55 which was solved by servicing the injectors.

  Also could be water vapour due to low air temperature, at bit like your breath on a cold day. Up here on the West Coast we often get very cool mornings, even in summer where the exhaust is visible early-on but wont be there at lunchtime.
 If you test it with your hand the vapour and water are only lukewarm even under load at 2-2300rpm. I'd only worry if the water is uncomfortably hot.

[PEA-JAY]

In my case it was steam. It vanished completely by the time it was 15 feet away and here temperatures would be around 30 degrees C so definitely not water vapour. Also no exhaust smell at all. It only steamed over 2800 to full RPM. Since I cleared the water inlet it stopped steaming all together. Problem solved 😊

[Scorcher IV]

I have considered the water vapour idea but it happens all the time and as Pea-Jay its gone a few feet from the boat. The injectors have just been professionally rebuilt and tested so its not unburnt diesel. The boat comes out of the water in June so I will put up with it until then and then clean the saildrive using a number of the methods advised, heres hoping.

[DT]

I recently installed a speed seal to my impeller housing , hard to quantify but it would appear to have improved the quantity of water flow thru the exhaust, reinstalled the impeller, so that's not it.
Anybody else had the same experience? as flow increase is not something speed seal sell themselves on.

[Odysseus]

I had a talk with the Jabsco engineer on steam and impeller life. He said both situations have the same probable cause in that there will be back pressure in the system. This causes cracks on the base of impeller finns.

Usally the back pressure is the heatexchanger but can be a pipe blockage. The life expectancies of a new impeller is 3 to 5 years. He recommended the fitting of a speed seal system, which I did some 5 years ago. I have only changed my impeller once. I take it out each winter and relube before fitting in spring.
 
If you disconnect the input pipe from the weed filter and blow back the water, you should be able to do this with a reasonable about of "blow" any difficulties will be a restriction.

Hope this helps

Odysseus Bav 38

[Neil]

Installing the speedseal definitely increased the flow on my D2-40. 

[Matay]

Can you please explain how speedseal increases the flow. To my understanding it is just a cover.
What am I missing?

[DT]

The best way to explain is to have a look at their website.
However the outboard side of the impeller that rotates against the housing, normally, is captivated by a disk that rotates itself so impeller does not have to distort it's shape to make a seal,  suspect this is why the flow improves.

regards all

[battuta]

Hmmm...I briefly had a SpeedSeal on, but then switched back when I had to install a new raw water pump, so haven't put it back on yet.

I'm not entirely convinced that flow increases with the SpeedSeal. Why should it - the impeller blades and the rate of their turning is the same (notwithstanding perhaps some minor impeller distortion with the stock system). Plus it's hard to imagine if that were truly the case, that the dude who markets SpeedSeals wouldn't be advertising and promoting it as yet another advantage of his system.

Am I truly missing the boat on a big advantage of SpeedSeals here?

Riyad
s/v "Battuta" (2008 B31)
Vancouver, Canada

[Ronald]

That sounds very familiar with what is saw last year. A constant stream of small air bubbles.
Initially I also was working along the line of an air leak, but at the end it was a small blockage in the up stream side, I.e a few mussels stuck at the valve side.

How I found out was when i removed the hose from the valve and fitted another piece of hose to it which I cut just above the water line. This allows you to open the valve without any water ingress, but stream was not really powerful when holding the open end in to a bucket.

Then I inserted a long small brush and poked around at a certain moment the mussels and pieces of came up to the hose and the flow became stronger again.  I also used an air pump to push back. 

That cleared it for me and until now no issues.

Good luck

Ronald.

[Scorcher IV]

Hi,
I have quite a few things to try out when the boat comes out of the water in June to try and cure this, but with what people have commented it would seem to be a poor seal on the raw water filter and blockages probably marine growth inside the saildrive. i intend to remove all the hose and ensure they are also free of debris, I am also tempted to install another separate raw water intake but not sure where I would position it. If anyone has already done it I would be grateful for the advice.

[Scorcher IV]

Just as an update I was at the boat yesterday and tried cleaning the seal on the raw water filter then lubricating it, which has reduced the amount of bubbles however when viewing the pipes upto the anti-syphon valve there seemed to be more on the out side than the in. I disassembled the vetus valve and cleaned the seat which was quite grimy (first time I have done this) the spring in the valve seems very weak. Still have the bubbles but a lot less, I am wondering if when the flow increases with revs it sucks the valve open allowing air into the system and therefore reduces the water through the heat exchanger. I have ordered another one (eBay £56) rather than £86 from dealers and hope that will help. Will still try the other solutions when the boat is out. Incidentally has anyone replaced the Volvo Penta strainer with a clear model and if so which one. Simon

[Symphony]

Vetus have clear bodied strainers of similar capacity. Make sure you get the correct size spigots ass they are made for specific sizes.

[Holger]

The bubbles you describe make me remember a similar problem we had some years ago. After cleaning the  parts of the sea water filter I made a mistake: I had put the seal loosely on top of the strainer / insert and the pressure plate on top of the seal. Some air was getting into the system but there was still enough water which avoided the alarm. However, the noise from the exhaust was different and in particular when it was cold there was some smoke. I have spent a lot of time on finding the problem. In the end I only had to attach the seal around the top of the strainer / insert and put the pressure plate on top and everything was fine again. I am not sure whether this is relevant for you but I thought I would mention it. Good luck and best regards Holger