I am maintaining a 56' Princess with Volvo TAMD 122 EDC engines. We have pitched the props, changed all filters and fluids, fuel tank cleaned, bottom cleaned etc. . .
In the past the owner has had volvo computer hooked up, had the injection pumps removed and checked.
The back of the boat is nasty after a couple of hours of running. Has anyone with this model boat had this problem? Any other model?

When you say the props are pitched, are you running at full RPM rated for the engines? I would expect any engine running at full RPM to create a far bit of smoke on the stern as the engine is working flat out but on the other hand, if you are just running at cruising speed then excessive smoke build up is not normal.

I would say that in 15 hrs running you should see signs of smoke staining the hull - I don't think there is alot you can do but I do know something that will help.

We have used Autoglym "Radiant Wax" polish and "extra gloss protection" on the boat for the past few years now and it really does keep the gelcoat shining for much longer - even at the stern.

The smoke is at cruising speed and way above normal. Fuel additive has helped a little.

In the past I had to wash the transom after just some hours cruising.
I did all you listed without any improvement. Then I bought new turbos. That helped some (I did't get any more revs though, the original reason for my doing everything).

The big change came this season when we were forced to start buying automotive diesel fuel (high taxed) instead of heating oil (low tax) in the past. The automotive fuel has eliminated almost all the smoke. I have washed the very slightly sooted transom only twice during 140 hrs this season.

I propose that you import your fuel from Finland. The price is just a mere 8 USD/ gallon.

You'r turn next season Mark.

That's interesting Stefan, obviously that proves the point of low sulphur road diesel. Problem is from november 2008, UK boaters will be forced to pay $11.60 a gallon for the same high sulphur red diesel !!! this is going to make travelling and running a motor cruiser prohibitively expensive for 99% of motor boaters. I think we could see alot of motor boats either for sale or just sitting tied up all year.

Yes the pricing of fuel is interesting. The price I indicated in the previous message was a calculation from our 1,45 euro per litre to US gallons. I have paid between 1,40-1,50 this season. Last year 0,75-0,80.

Should be abt. the same as your sit I think.

According to all Volvo marine instruction manuals...

low sulphur content "city Diesel" reduces performance by 5% and increase fuel consumption by 2-3%

Mitchak

Have you discovered anything wrong with the boat so far? When was the last time the boat hull was antifouled/cleaned?

Are the engines running normally otherwise? is full rpm being achieved?

Excessive black smoke points to unburnt fuel which can either be too much fuel being supplied or not enough air for combustion. Are the engineroom intake fans blowing air into the engineroom? are they functioning? Is the turbo runnning freely?

The bottom is clean and the air supply is something to check out. I have been running a Bell Performance product "Dee-Zol" in the fuel and the smoking has disappeared. Fingers are crossed and I am now a dealer for Bell Performance. Thanks for all the suggestions.

I would be most interested in this Bell Performance Dee-Zol, what is it?