Turbo Soot Buildup

[ArranP]

There is a build up of soot on the Turbo Exhaust Outlet so much so that eventually it prevents the turbine wheel from turning.

I dismantle the turbo and file away buildup of soot in the exhaust housing and the turbine wheel spins freely again.

Is there a paint I can use on the exhuast outlet housing to prevent soot building up/ clinging to its surface ?

Thank you for feedback.

Regards
Arran.

[rslifkin]

If it's sooting up that badly, I'd expect it's not normal. Does the engine reach rated RPM at WOT or is it over-propped? If it's over-propped that can cause more soot.

Another thing that can cause it is running slowly all the time and never working the engine hard. In that situation the exhaust never gets hot enough to burn off the soot, so an occasional hard run may help avoid this problem.

[Turtle Blues]

Turbos can be professionally cleaned and ceramic coated. Usually done on large or high performance equipment. You cannot do it yourself. Cleaning and sanding/polishing the throat - PAST the close tolerance part of the rotating assembly can help but as said above preventing the build up is preferable.
How many hours do you operate before clogging is a problem?

[FPNC]

1) The EGR valve if it has one.

2) Worn rings.

3) Too much exhaust back pressure. Check with a gauge.

4) Oil seal leak on the hot side of the turbo caused by to high exhaust temp. (see 1,2,3)

[SailingHarmonie]

Here is another cause of excess exhaust soot that I have some personnel experience with: improper injection pump timing.

On engines where it is set by rotating the pump, or other non-shim method very, very few mechanics actually follow the recommended procedure. Instead they do it “by ear”. It is just too much time and trouble to get out the dial gauge or other special tool recommended. It is frequently not correct, and excess soot can be a result.

On efficient method for removing the soot buildup is oven cleaner. Just do not use it anywhere near aluminum parts.

[skipperpete]

Is this still the same Yanmar 4JH 110 that had a bent turbo shaft back in June 2023? If so, the intercooler might be blocked…. Or simply that the new turbo has failed (again), how’s the compressor looking? Have you been using the boat continually or has she been idle? The sooty turbo problem usually starts the other way around, first , corrosion in the turbine scroll from the high humidity in the aqualock builds up and gently holds the turbo wheel and THEN with no boost and plenty of fuel the heavy smoke appears and soot quickly blocks the turbine chamber and scroll.

[Lepke]

Soot is unburned fuel. Usually from some engine insufficiency or long hours at low loads.
You could try running a high rpm for an hour during your trip or add a cetane booster to your fuel.

When I was young, oil companies competed to offer the best diesel for power and economy. Now the formulations are for emissions and low sulfur with a big loss in lubricity. I run Detroits with mechanical injectors so lubricity is a big deal to me.

60 years ago, running sisters to the engines I have now I didn't use a fuel conditioner. But now I use one every fueling.