white "smoke" = problem ?

[bobgosling]

white \"smoke\" = problem ?

Returning to my mooring today I had a lot of white "smoke" coming from the exhaust. Not billowing out, just enough that I noticed that it was abnormal. The reason for the quotes around smoke was because I'm not entirely sure whether it was smoke or steam.

My first thought was "oh damn, the impeller has gone again". But I looked over the stern and I had the normal output from the exhaust hole ( it's never been a constant stream , more of a baling out with a teacup scenario ). On arrival at the mooring I opened the engine compartment up and while admittedly warm it didn't appear excessively hot.

Father-in-law had been helming and is a bit of a speed freak so revs had proably been higher than normal. I also found a bit of weed in the seacock filter ( not much though ).

What should I be checking next ? White smoke normally implies water in the combustion mix doesn't it ?

Any suggestions gratefully received ! I don't have much experience with diesels.

 

[Guest]

Re: white \"smoke\" = problem ?

White smoke is un-burnt diesel.

The difference is that white smoke upsets your neighbour and steam disappears before it get that far. (Marina distances).

 

[Parsonsheath]

Re: white \"smoke\" = problem ?

Noted your comment as my volvo always does this, and folk are kindly pointing it out to me, but in the 3 or so years we have owned the boat it has proved totally relaible.

We did replace the thermostat last year and did an oil change and filter and impellor,, none of these had any effect, would it be any use to have the injectors reset or reconditioned, or is there like to be any more serious problems building up?

 

[MarkJohnson12345]

Re: white \"smoke\" = problem ?

Basic diesel engineering says that white smoke is a air filter problem.

Clean or replace might be the first step.

Good luck.

Mj

 

[fireball]

Re: white \"smoke\" = problem ?

Ah - now Air filter I can do easily! ... take it off, give it a wash'n'blow dry ... (it doesn't need another perm yet! /forums/images/graemlins/blush.gif) .. /forums/images/graemlins/smile.gif

 

[bobgosling]

Re: white \"smoke\" = problem ?

Filter was replaced during the service last year. It's just a simple sponge tube on a Beta 20hp. I'll take a look though.

Thanks for all the advice. Keep it coming !

 

[boatmike]

Re: white \"smoke\" = problem ?

You have probably answered your own question. Weed in intake, more throttle than normal = a bit of steam. Steam is very easy to identify as it quickly dissipates. Try again with normal throttle and clear intake and it will probably be OK.
You don't say what engine or if it is raw water or fresh water cooled but your "baling out with a teacup" syndrome sounds as if the flow is restricted anyway. It may be that it is a fairly old engine and needs the waterways clearing or in the case of a heat exchanger, the tube stack cleaning. No it does not mean water in the combustion, just insufficient flow in the exhaust.

 

[Guest]

Re: white \"smoke\" = problem ?

[ QUOTE ]
White smoke is un-burnt diesel.

The difference is that white smoke upsets your neighbour and steam disappears before it get that far. (Marina distances).

[/ QUOTE ]

????

White somke is too much air in the mix or steam .... Black smoke is too much diesel in the mix. As I was told ...

My engine "billows" white smoke when first started and then settles down to a lot less when warmed and normal running.

As to amount of water that passes through my system ... at tickover its a good mugful every few seconds ... at fast speed - its a good pump and becomes a mad gush of water ... (Perkins 4-107 raw water cooled)

 

[whipper_snapper]

Re: white \"smoke\" = problem ?

This may sound daft, but was it a misty/foggy day ?

On such days, it is easy to be fooled into thinking there is something different about the amount of white smoke you are putting out when it is just water immediately condensing into vapour on hitting cold, water saturated air.

 

[oldharry]

Re: white \"smoke\" = problem ?

Diesel 'white smoke' is actually raw diesel fuel as sprayed from the injectors, passing through the engine without ever igniting. As pointed out, it causes complaints from the neighbours as it smells really bad. Older engines will produce a bit of diesel smoke on start up until the engine settles down, and other than the nuisance to neighbours is nothing to worry about.

Nearly always 'white smoke' reports from marine diesels are steam from the water cooled exhaust, usually because the water flow is restricted and the exhaust is overheating. Some engines - notably Bukhs - do it all the time.

Over enthusiastic use of the throttle and a partial weed blockage of the water inlet would be more than enough to produce steam on an engine that spits coolant out in cupfuls rather than producing a regular flow.

If it is genuine diesel fog 'white smoke' then you have fuel starvation (not air starvation - that causes black smoke), possibly because of: partial fuel filter blockage, faulty injection pump or timing, injector problem, low compression (valves or rings), faulty fuel lift pump - as the common causes!

 

[doug748]

Re: white \"smoke\" = problem ?

I had an engine where this problem got steadily worse over two seasons, turned out that the steel pipe from the cylinder heads to the injection bend was bunged up with salt. Boatmike and Oldharry might have the answer to this one.

 

[Guest]

Re: white \"smoke\" = problem ?

[ QUOTE ]
Diesel 'white smoke' is actually raw diesel fuel as sprayed from the injectors, passing through the engine without ever igniting. As pointed out, it causes complaints from the neighbours as it smells really bad. Older engines will produce a bit of diesel smoke on start up until the engine settles down, and other than the nuisance to neighbours is nothing to worry about.

Nearly always 'white smoke' reports from marine diesels are steam from the water cooled exhaust, usually because the water flow is restricted and the exhaust is overheating. Some engines - notably Bukhs - do it all the time.

Over enthusiastic use of the throttle and a partial weed blockage of the water inlet would be more than enough to produce steam on an engine that spits coolant out in cupfuls rather than producing a regular flow.

If it is genuine diesel fog 'white smoke' then you have fuel starvation (not air starvation - that causes black smoke), possibly because of: partial fuel filter blockage, faulty injection pump or timing, injector problem, low compression (valves or rings), faulty fuel lift pump - as the common causes!

[/ QUOTE ]

I'm now confused ... various mechanics ahve told me lack of air in the mix causes black smoke from partially burnt carbonised fuel ... white smoke from too much air when fuel is not getting through and so mix is far too lean.

My engine exhibits white at tickover and slowly changes to black at near full chat ... explained to me as lean diesel / air mix at low revs ... over rich diesel / air mix at high revs ... possibly due to worn pump and the sticky rings I have. In fact pump has just given out ... so awaiting replacement now ...

Not arguing - just confused after what was told to me by Diesel mechanics ... (My truck does it as well - and that engine has been rebuilt top to bottom ... )

 

[Guest]

Re: white \"smoke\" = problem ?

White smoke gets complaints as opposed to helpful neighbours just pointing it out excessive steam.

Black is partially burned diesel. It is just carbon that had no way to burn to CO2 or CO. Main cause is way too much fuel for the revs. Either engine labouring (Weed etc) or too much injected (eg. engine fault). Or air restricted.


White is un-burnt diesel that never had a chance. This is due to drippy injectors, bad timing on the injector pump (diesel arrives just too late), or terrible compression on one cylinder. If a cylinder does not fire at all you get white smoke.

The other way to get white smoke is to have a 4.108 that has a faulty cold start unit that is leaking diesel into the air intake. The cold start is a electrically heated diesel blow torch.

 

[Bilgediver]

Re: white \"smoke\" = problem ?

This is probably water vapour/steam and it can seem worse on dreich damp days and much worse in damp nights when the atmosphere ... and much better on hot summer days.... if steam it clears as it floats away from the boat...white smoke stinks..

 

[SailJonah]

Re: white \"smoke\" = problem ?

My white Smoke was cured by Cleaning the system of Diesel Bug and then Geeting the injectors serviced. I had 2 Injectors that where Blocked, and 1 operating. The Blockage had been caused by Diesel bug. Once Clean and Fresh injectors, I was back up and Running. Worth the investment in the ovehaul. If you have diesel Bug, replace the Tank to engine pipework as that was all blocked too.