Smokey Volvos

[matthewc]

I have twin AQAD41 Volvos which emit a cloud of black smoke when pushing the throttles forward to planing speed. This leaves soot and smears on the stern. Performance is good however. Ventilation appears ok although there is less smoke when the engine hatch is open. However there is still smoke. Is it injectors/injection timing?

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[Col]

The fuel rack opens at about 2500rpm, and the turbos come in at about 2700rpm, so you have a situation where engine is slightly overfuelled for a 200rpm window. If this matches the speed that your boat starts to "climb the hump" then the smoke will be more noticable. (You haven't said what boat it is) Dirty injectors will make it worse, but the fact is AD41's do smoke, the AD41a's more so than the AD41b's

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[Nick2]

What boat Mattew?

Nick

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[Col]

Wondered when you would appear /forums/images/icons/laugh.gif

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[matthewc]

Thanks Col,
Boat is a Sealine 328

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[matthewc]

Thanks Nick,
Boat is a Sealine Sovereign 328

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[Nick2]

From my experience with the same basic engines - prop repitching to increase revs and ventilation, ventilation and ventilation......

I have also done injectors but hunch and only hunch is that the ventilation increase has been the most important factor.

Any queries ask Col as he is very clever on this sort of thing....

Nick

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[simongoldthorpe]

Hi Nick

How did you increase ventilaation?

One of my TAMD 41s has gone back in this week after a £6000 rebuild (not including cost of gettting it in and out) so I am hoping that at least one of them doesn't smoke.

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[hlb]

Well it will be the only one on earth if it does'nt.../forums/images/icons/smile.gif

<hr width=100% size=1> Get Yer Flags ear</font color=red>
Haydn

 

[simongoldthorpe]

Thanks Haydn that's very reassuring!

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[Talon]

Matthew,

We have a Sealine 305 and have exactly the same issue with our AQD31's, you open it up and the water turns black for about 30 seconds or so then clears.

The first time I saw it I shouted at my Dad to shut down, I thought my engines had shat themselves!!! /forums/images/icons/frown.gif

However we found that every time we open up it does it and clears.

We also suffer with black stains all over the back of the boat, we are using Soltron at the moment to see if we can improve it. I must admit, so far it seems to be working okay, whilst the black smoke is still there the marks on the back of the boat clean off easier... /forums/images/icons/smile.gif



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[stellican]

We had the same smoke problems in our targa 33 we removed the air filters which made improvement but there is no real cure you just have to live with it . problem is it makes a terrible mess and probably no good for your health. The problem was also at tickover on ours. In the end we sold boat.

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[stellican]

We had the same smoke problems in our targa 33 we removed the air filters which made improvement but there is no real cure you just have to live with it . problem is it makes a terrible mess and probably no good for your health. The problem was also at tickover on ours. In the end we sold boat.

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[matthewc]

Thanks everyone,
Interestingly no-one seems to think its injectors.
The problem is better with the engine cover open so I am going to install more and bigger ducting.
I will post a message with the results.

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[oldgit]

Curious this.My 40As emit a bit on start up but this soon clears.I can not detect any trace of smoke when throotles wound open but can spot what looks like a whisp of steam when flat out and water drops well down on transom.Can only assume that being an outdrive boat most muck is being drowned by exhausts being under water.

<hr width=100% size=1>If it aint broke fix it till it is.

 

[alastair]

Had a similar problem with my AQAD40Bs. I think its a process of elimination. Assuming your fuel is ok, the order in terms of easiest and cost for me is:
1 Ventilation, like Nick said. - Are the air filters clean? As previously posted, run with the engine hatch open to test if enough air is available to the filter intakes
2 Clean the turbo intakes - this was my problem, and made a massive improvement.
3 Props - are you overpitched
4 Injectors
5 Lift pump

Good luck, its nice to avoid a clean up job after each passage

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[dgk3dr]

Thanks Col,
Boat is a Sealine 328

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[dgk3dr]

matthew do you still have your 328 if not can you rememeber what prop size you had on it ?I think mine has a5 im sure they should be a6
mine puffs a bit of black smoke if its not doing 20 knots or more heavy boat ad41s are at their limit I think

 

[Greg2]

matthew do you still have your 328 if not can you rememeber what prop size you had on it ?I think mine has a5 im sure they should be a6
mine puffs a bit of black smoke if its not doing 20 knots or more heavy boat ad41s are at their limit I think

Not sure if you realise that this therad is 15 years old. Worth trying the Sealine Froum

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[dgk3dr]

tried that everyone is saying different ! never know matthew may still have his trusty 328 !