An exhausting sooty matter!

[seafox]

Alan Wheeler
Senior Cruiser. I won't go any further with the excellent advice given all ready, but I will nudge this thread a little to another aspect. Just how bad is the soot. Is it possible there is some other issue here?? There should be little noticible black smoke. If there is a lot and it is badly sooting up the side of the boat, you have some other issue. And no, exhaust will not be the issue, so if I have understood the excersise correctly, the guy is on the wrong track.

I thought I would start another thread about soot.

We have just bought a new Volvo MD2040. We replaced a Yanmar 22hp as it was sooting the transom up all the time.
The new motor is a bit gruntier and so pushed the old exhaust under the water. It has sooted up the transom from day one. The motor has now done 30 hrs.

I can also smell a slight unburnt diesel smell.
There is no noticeable black smoke coming out of the exhaust.

The motor revs at 3550 max while motoring, (the Vovlo man said it should be 3600rpm) so the prop pitch must be ok.

The Volvo guy has shifted the exhaust to the side. We have only motored from the travel lift to our berth and already I can see some soot starting to appear.

As soon as this shitty weather passes I am going to have a motor for a few hours to see how much soot appears.

How much soot do you get?

[GordMay]

Soot:
Diesel Particulate Matter (DPM), as defined by the EPA regulations and sampling procedures, is a complex aggregate of solid and liquid material. Its origin is carbonaceous particles generated in the engine cylinder during combustion. The primary carbon particles form larger agglomerates and combine with several other, both organic and inorganic, components of diesel exhaust. Generally, DPM is divided into three basic fractions (Figure 1):
~ Solids - dry carbon particles, commonly known as soot,
~ SOF - heavy hydrocarbons adsorbed and condensed on the carbon particles, called Soluble Organic Fraction,
~ SO4 - sulfate fraction, hydrated sulfuric acid.

The actual composition of DPM will depend on the particular engine and its load and speed conditions. "Wet" particulates can contain up to 60% of the hydrocarbon fraction (SOF), while "dry" particulates are comprised mostly of dry carbon. The amount of sulfates is directly related to the sulfur contents of the diesel fuel.

Soot’s exact composition is difficult to characterize because different engine technologies and conditions produce different types of soot. Indeed, the smoke clouds coming from diesel engines can even have different colors. For example, blue smoke (mainly oil and unburnt fuel) can indicate a poorly serviced and/or tuned engine; black smoke (soot, oil and unburnt fuel) can indicate a mechanical fault with the engine; and white smoke (water droplets and unburnt fuel) is produced when the engine is started from cold and may disappear when the engine warms up.

[BC Mike]

Go to the photo gallery, then to monohull sail boats, then page three, look for Gently AP photo and click on the photo to make it larger.
That is about where the exhaust should come out on a boat with a large transom and a transom hung rudder. Also you can see what three months worth of exhaust looks like on the transom.
I am guessing at three months but that seems to be about how often I might actually clean the black stuff off. If anything it is longer in between. I was going to ask if the engine might be running a bit rich. That would be a question for whovever you bought the motor or the Volvo dealer.
Your photo does not show if there is a tansom platform on the port side. My platform is to Starboard and not shown on my photo.
Michael

[seafox]

thanks
Mine was looking like that after two hours and on both sides of the rudder.
My platform is on both sides.

How is the intake on your engine set-up? Is your engine compartment vented, and about how many cubic feet is the compartment? You may have an airflow issue. THe neewer engines should not produce any visible soot. As for residual soot on the transom, too much too soon. You have a problem, and it needs to be solved soon. You have potential to cause damage to your injector tips, loose power, and any number of other inconveniences.
BY the way, want to sell the old Yanmar?

[seafox]

We are on to the volvo dealer and he is apparently "on to it".
He wants to go out on another sea trial to see if the exhaust not now going in the water makes any difference. Next calm day hopefully.
I sold the Yanmar to a guy in Auckland for $5000. I had spent over that on the injectors and pump manifold etc in the last year so he got a bargin.
The side of the motor box has been off throughout all of this (where the photo of the manifold was taken through in the exhaust thread) so plenty of air.

[BC Mike]

Where are you located and what kind of boat do you have.
I was in Auckland for a while and am familiar with a few of the NZ boats. Played for Suburbs in Avondale.
Michael

[seafox]

Wellington and a Lotus 10.6

Oh well, would have cost too much to ship anyway
Sounds like the xhaust is the likely culprit. Good luck. Glad to hear the dealer is wiling to stick with it, as opposed to sticking it to you.

[seafox]

We have just been given a new 30hp under warranty. Volvo tried all sorts of things with the 40hp and ultimately took it back. The whole job, boat builder for engine bed, travel lift, prop etc was covered by our local Volvo dealer.
Boat now goes faster and not a trace of soot or unburnt smell.
The motor is the new D1 30 series

[Alan Wheeler]

How interesting. Hey, Did they change the prop???
And did they increase the air intake????

[seafox]

Prop was the same dia 3 bladed volvo, just a slightly dif pitch.
Air intake, nup. It is in the same engine compartment. Lots of air space inside it. Tons.
Out again today. Done 8 hours now. Still no soot.
Passed a Ross 930 in full sail. Caught him and circled him and then passed at 6.5 knots at 2400 rpm.
I am very happy now!