I have been dealing with this for 6 years. My port engine soots quite badly. I have tried all the obvious solutions- new injectors (twice), fuel sep, turbolators, setane booster and changing prop pitch. My props are n ow pitched at 7 which means my top speed is about 9 knts. I have 3 ideas, one is since it is black smoke (not overly damaging to engines, just unburned fuel), is to figure out how to burn fuel again, introduce more air into the engines (how would I do that), or change the exhaust so to vents outside of the envelope as the station wagon effect brings the smoke into boat. Help!!!
440 express ongoing sooting issue
- Thread starter Gibsri
- Start date
- Jul 16, 2020
- 1,891
- Boat Info
- 1999 450 Express Bridge, 9’ Achilles dinghy w/15hp Suzuki EFI
- Engines
- Caterpillar 3126TA
You may want to run your question in "Diesel Engines/Drives/Transmissions/Props" section for a better response. Also specify which Caterpillar engines you have in your boat.
One of the items to look at is are the engines overloaded. A 1995 boat when it originally came off the line might be a lot heavier 27 years later. Typically the easiest fix is a prop change which you have already done. A top speed of 9 knots seems really slow however for a semi-displacement hulled Sea Ray. What RPM are you running at at top speed? Do you have a boost gauge and a pyrometer gauge to measure your engine load? I wonder if the one sooty engine has a falling boost pressure and increased exhaust gas temperature characteristic of a failing turbo charger?
- Jul 16, 2020
- 1,891
- Boat Info
- 1999 450 Express Bridge, 9’ Achilles dinghy w/15hp Suzuki EFI
- Engines
- Caterpillar 3126TA
I looked at your prior posts on CSR about this issue dating back to 2018. Frank Webster gave you this advice.
“Billowing black smoke is usually a sign of unburned diesel fuel in the exhaust. That can be from restricted intake air flow due to dirty air filters, blocked hull vents, a collapsed hose on the intake, fouled aftercoolers or a turbocharger problem that is limiting the air intake. Other causes may be a fouled or damaged injector tip making the injector spray fuel dropplets rather then atomizing it.
Unfortunately, the typical boat owner cannot diagnose or repair most of the above. Suggest you get a Caterpillar mechanic on the boat to diagnose and guide you.”
I agree with Frank. I also see that you have from your old posts a 440 Express Bridge with 3116 Cats which is very similar to my 450 Express Bridge with 3126 Cats. A top speed of 9 knots is way to slow for your boat. You should be cruising at 17-18 knots with a top speed in the 20s.
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Thank you for your comments and since 2018 I have followed the advice from Frank Webster. It made no change. The only thing that has helped is changing the pitch on the props but till gwetting sooting. Cat mechanic says (after two sets of injectors and 10 hours of troubleshooting that there is nothing wrong with the engines, Starboard does NOT soot. Port does.Cat Mechanic said that in some cases a CAT engine soots.
- Jul 16, 2020
- 1,891
- Boat Info
- 1999 450 Express Bridge, 9’ Achilles dinghy w/15hp Suzuki EFI
- Engines
- Caterpillar 3126TA
I’m certainly not a professional mechanic, but the advice to repitch your props to the extreme where your top speed is 9 knots seems very suspect to me. They turned your cruiser into a trawler maybe to mask the problem instead of solving it. If your max speed is 9, do you cruise at 7????Do you ever hear the turbos spool? My advice is to get another Cat mechanic to look at it.
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I haver had three different CAT Mechanics from two different companies and they all agree. FYI. changing the pitch on the props was not advice from the CAT mechanics. The one company with two different mechanics was actually the CAT dealer.
Did these mechanics test boost and EGT as questioned above?
- Jul 16, 2020
- 1,891
- Boat Info
- 1999 450 Express Bridge, 9’ Achilles dinghy w/15hp Suzuki EFI
- Engines
- Caterpillar 3126TA
The other question I had that wasn't answered was did the turbos ever spool with a 9 knot top speed?
More questions for you:
1. What oil are you running?
2. Did your mechanic check the turbo charger compressor and aftercooler core? The fouling of the turbocharger and aftercooler can cause reduced air flow, loss of power, and increased black smoke/soot.
3. Have you run with the ER hatch open as a test to see if there is any air restriction?
4. Have you looked for boost air leaks at post turbo hose tubing connections?
Gibsri: You should probably post this question in the 3116/3126 thread in the "Diesel Engines..." section of CSR for a better response. Please check the thread often as that topic moves quickly. You will be getting a lot of questions thrown at you in order to diagnose and possibly suggest a remedy for you. If you don't respond timely, your questions might get passed.
Here is a link: http://www.clubsearay.com/index.php?forums/diesel-engines-drives-transmissions-props.51/
Just trying to help
- Jul 16, 2020
- 1,891
- Boat Info
- 1999 450 Express Bridge, 9’ Achilles dinghy w/15hp Suzuki EFI
- Engines
- Caterpillar 3126TA
I’m not sure anyone can help you. No Sea Ray cruiser owner I have ever seen or read about his modified his props to make the top speed 9 knots or thought about adding 12” exhaust elbows.
I did have a friendly conversation with another 440 Express Bridge owner this past holiday weekend. He had a 1996 with 3116 Cats. I asked him if he had any sooting issues. He said a little, but it wasn’t bad. I then asked what his cruising speed and WOT speed were. He said around 17 knots and in the low 20s WOT. The “station wagon effect” doesn’t apply when the boat is operated at the designed speed. I checked over in the Diesel Engine section and did not see a post from you. Why not????
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