Black smoke and soot on stern of boat

[Frank Masseria]

My engine is a 330hp 6bta (CPL 1975). Last year when the engine had 5400 hours I had the fuel pump recalibrated to CPl 2208 (370 hp)
and changed my fuel injectors to match the new fuel delivery. I have put 1300 hours on the engine since that modification.
The engine pushes a 27 foot down east boat that I use as a fishing charter boat.

Lately I have been leaving a smoke haze on the water especially on windless days and hi humidity. The back of my boat is full of soot and I can see the puffs of black smoke while under way. The smoke begins at around 1600 -1800 RPMs. It doesn’t get much worse when I run at cruising RPMs of 2200-2400. But the smoke is visible.

The engine runs perfectly and gets up to 3000 RPMs under load. I was thinking I was having an air issue so did the following to see if that was the issue.
1. cleaned the after cooler
2. cleaned the air sep system
3. inspected turbo blades on intake side and seem fine.
In addition I installed new injectors thinking one could have been bad.
I went even further by removing the airsep completely and ran a hose to a container for the crank case gases to eliminate blow by (don’t see any) and possibly shooting oil back into the engine from the airsep into the turbo.

The smoke is still visible.

Any suggestions on possible causes. I was wondering if the AFC needed a slight adjustment. Could my fuel pump (P7100) be over fueling the engine?

Thank You for any suggestions

Topic

[Rob Schepis]

I’d like to see a reply to my post … that exhaust looks totally unsafe, especially for a charter fishing vessel.

[Tony Athens]

Your problem is real simple…………..You need to loose 2″of pitch.. I have never seen a 370 able to pull at much prop as a 330 that was already propped out. With your current 2208 fuel calibration, this engine needs to see 3150 RPM and see it easy..

Your pics–Send them to me direct in High res…. [email protected]

Tony

[Frank Masseria]

Thanks Tony

Here are the responses I presently have

1. Engine tach was checked at various RPMs with a digital tach. The numbers appear to be very accurate, I shot it at 2400, 2500, 2600, 2700 and 2800 in neutral. I had the mechanical tach dial right on these number, The digital was within 5-10 RPms for every one.

2. The after cooler was taken part (it is Copper) and boiled in a solution that removes grease and oil. The unit came out very clean. It was reassemble with the grease that I purchased from you along with new O rings.

3.The prop is the same as the 330 calibration but I had one inch of pitch taken out. At the beginning of this season the boat with our a full compliment of people toped out at 3067rpms

4.With the the 330 we only reached 2750 at best during the beginning if the season

5.Right now I can reach 2975RPMS wth the boat loaded as during its normal operation

6. I have not been able to measure boost yet but will shortly

Im attaching pictures of engine

[Rob Schepis]

Frank Masseria wrote:

3. inspected turbo blades on intake side and seem fine.

All this tells tells you is that the engine is not on a “salt air” diet and that the turbo has not ingested a pc of debris damaging a compressor fin. When was the last time you had the exhaust apart to inspect the turbine side of the turbo? That is what will tell you if the engine is on a “salt water” diet … hence Tony’s questions on seeing your exhaust and any boost measurements.

Looking fwd to your responses to the above and to each of Tony’s specific questions …. As always, the best of answers get the best of help.

[Tony Athens]

6BTA 5.9 370 that was re-calibrated from a 330

Here is what you need to do “as a best way” to solve this and get some solid input back from me.. Follow this as written..

1) Tell me you have calibrated your tachs accuracy in the 2400-2800 RPM range at the dock in neutral using a strobe–Give me real numbers, 2600 instrument tach = what strobe RPM?

2) Tell me when and how you cleaned the aftercooler? Got pics of it on the bench dissembled? Were the sore fins cooper or aluminum?

3) Tell me if the prop you have on the vessel is the sames as it was with the 330 calibration?

4) What RPM did you reach with the 330 with the vessel loaded equally .

5) I want to “see” your exhaust system as installed in the vessel.

6) RPM you can reach on the vessel tach, loaded as you use the vessel– 3000, or maybe squeaking 3000 under best case scenario?

7) Do you measure BOOST and / or EGT? When yo ask it on on and engine of this class, this is essential if you want to sort out anything like this..

SEVEN numbers — I want SEVEN well thought out / accurate replies..

Tony

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