Grey Smoke from Bukh 20?

[Wardy]

My Bukh 20 on the Westerly konsort gives off grey smoke from the exhaust; the more power on, the more smoke. It doesn't smell of oil or fumes and appears more in the way of steam (Not sure whether it is). It seems to evaporate after it has emerged.
How do I get rid of it? it's more embarrassing than anything else, blasting through Harwich with a smoke screen behind James Bond style.

Will check back next week to see if anyone else has had a similar problem.

(It's time that Woolverstone got WIFI!)

 

[cliff]

I had same problem on my DV24. It was so bad I was considering hauling the engine out but thankfully it is a relatively simple problem to rectify.

If as you say the "grey smoke" disappears quickly (within a few feet of the boat) then it is more than likely steam from the exhaust rather than an injector / pump problem. I had the injectors and pump reconditioned on mine bit the problem did not ease any.

To cure the ailment first remove the exhaust elbow and water injection hoses between the pump and thermostat housing and between the thermostat housing and the water injection point. At this point you should also remove the thermostat housing / cover.

Next is clean out any carbon deposits / corrosion build up inside the exhaust elbow (big screw driver an some brute force and ignorance) check inside of the elbow to make sure the injection point is clear of any obstruction.. Do the same with the thermostat housing / cover inlet and outlets (I had to drill these out on mine).

Check the hoses for any obstructions and also check the pipe mounted on the front of the engine is not blocked. refit everything except the final injection union and start the engine - you should have a good flow of water through the injection hose. Shut the engine down and fit the final union.

If there is not a good flow then check your pump impeller and inlet piping including the strainer (might be a good idea to check these first /forums/images/graemlins/crazy.gif)

Now this should restore the exhaust cooling to normal but do remember the exhaust will still steam a little when working hard (according to Bukh U.K.) but it is nothing to worry about, likewise a little oily film on the water immediately after starting or when when ticking over for extended periods. Seems this is something to do with the piston crown not being hot enough and a minuscule amount of unburnt fuel goes out the exhaust.

Do also check the pencil anode and replace it if needed (I go through 2 every season).

If you want to clean the internals I used Fernox boiler descaler and recirculated the discharged water from the exhaust back to the engine. The engine was flushed with fresh water first then once I was happy the salt water was all gone I started recirculating the coolant and added the fernox. During an hours running I had to top up the coolant bucket with maybe 5 gallons of water, adding a little more fernox each time. Really did clean the internals.

Hope the above helps
----------

“Artificial intelligence is no match for natural stupidity”
Skype id:cliffillupo

 

[oldharry]

I agree with Cliff: if it is not pungent, and disappears quite quickly, its steam.

My Bukh steams slightly near full thropttle, because it has quite a long exhaust pipe. If there is enough steam to cause comment, then as Cliff says, there is not sufficient water coming through to cool the exhaust properly, and a bit of de-scaling and cleaning is all (!) that is required to sort it. But you will never competely get rid of it on a Bukh.

 

[asj1]

Re: Grey Smoke from Bukh 20?

I agree Bukh's do steam somewhat. On mine it tends to cycle from a fair amount to not very much over the course of 10mins or so. As I have replaced all the hoses, impeller, and had the cylinder head and manifold off during the winter I believe the cycling is due to the thermostat working properly - which I know it does as I tested it in a pan of water when everything else was apart last winter. I'm in Ipswich so could compare steasm sometime!

 

[Wardy]

Thanks for the excellent advice.

Sorry i took so long to get back to a terminal but I have cleared the pipes and connexions as prompted and it seems to have done the trick. I also installed a new anode too boot.
The exhaust still steams a little but I can put up with that. The worst that happened was a total loss of water passing through the exhaust! It doesn't take long before the engine overheats. i Think the major part of my blockage was in the exhaust elbow. It's ok now though.

Thanks all

Steve (off to Ostend tommorrow)

 

[philip_stevens]

Steve,
keep a good eye on that injection elbow, as it can crack with age. Mine did, but I caught it before it disintegrated and would have filled the boat with water.

 

[wildernessdave]

I see this is an old thread, but my Bukh 20 has always steamed in really cold weather and there seems to be some smoke as well. Its possible there is a little more smoke than there was a few hundred hours ago, but it hasn't changed a lot since we got the engine and have put about 500 hours on it over the last 3 years. Below is 18 second video of the exhaust while running at 4.5 to 5 knots, which is our normal cruising speed. The exhaust doesn't really change drastically if the engine is idle vs near full throttle. The engine starts easily and runs well. The exhaust doesn't smell really bad. Over time we do get black soot from the exhaust on the stern of the boat left from the exhaust, which we clean off every month or two. We have been cruising full time for a little over a year.

The exhaust doesn't bother me, but I am just trying to figure out if it is a symptom of an underlying problem, or if its just the standard bukh engine steaming.

https://drive.google.com/file/d/1PcHphpS_46RIMseqtDAaj8CY2Z4krPGh/view?usp=sharing

 

[James_Calvert]

We have a Bukh 20.

Doesn't look bad to me.

Can't see from your video whether it quickly disappears =steam or hangs around = smoke.

 

[neil_s]

While motoring out over Chichester bar a couple of months ago, somebody stopped me and told me the exhaust was steaming and throwing out lots of black water and was it all right? This, despite temperature gauge indicating normal and the engine getting the full Fernox treatment last year. It seems that it's something Bukhs do. I was at full throttle, though!

 

[Champagne Murphy]

Normal. We have a BUKH 20 in our Sadler 32, I rebuilt the engine about 7 years ago with new wet liners, reconditioned injectors and high pressure pump. It didn’t make the slightest difference to the steam. 7 years on it still fires first time with no throttle.
Sooty bum is usual too, try to clean it regularly or it sticks.

 

[sgr143]

https://drive.google.com/file/d/1PcHphpS_46RIMseqtDAaj8CY2Z4krPGh/view?usp=sharing

Our Bukh 20 steams a lot more than that! I'll have another check over the whole cooling circuit this winter in the vain hope that next season it will steam less. I think the main culprit at present is likely to be a restriction in the inlet grille (possibly years of build-up of antifoul), as I checked the "poker" last winter, the innards of the bits of pipe around the thermostat and elbow only a month ago, and "decoked" the thermostat housing before our trip last weekend. We still had a kindly soul on a passing boat waving madly to get our attention as we exited Portsmouth in case we hadn't noticed that our engine might be on fire!
Steve