Low RPM & Black Smoke

[NoSpeed]

I have Cummins 6BTA5.9M3 330 HP@2800 RPM engines installed on our 2002 Bayliner 4788. The engines have logged approximately 1470 hours. I routinely operate the engines around 1500 RPM and cruise at about 8.5 knots. A couple of months ago, I was requested to pickup my speed to make a bridge opening and discovered the port engine would not accelerate to its rated RPM. In fact, the boat following me reported black smoke billowing out our exhaust during acceleration. Fire-walling the throttle was no help. Consequently, I had my mechanic investigate. At the dock, we took the port engine to 3140 RPM with no hesitation or black smoke. The air filters were cleaned at the end of last season. The primary/secondary fuel filters were also replaced at that time and vacuum gauges were installed. So, he said it could be the fuel injectors. Consequently, he replaced all 12 fuel injectors with new ones. On our next outing in mid-Sep, it was discovered this did not resolve the issue. The port engine could not sustain any more than 1790 RPM and the starboard engine would not accelerate past 2340 RPM. The discovery of the starboard engine having the same issue was not noticed earlier since I was using symmetric power. Now, my mechanic thinks it is likely to be caused by a torn diaphragm in the fuel injector pumps and suspects the use of Biobor JF as culpable. It has been difficult to get back on his schedule. Rumor has it he may have a serious health problem. Anyway, do any of you think this could be it? I am mechanically inclined to do routine maintenance myself. Would this be a job I could tackle or is it over my head? Where do I get the repair parts without buying completely new fuel injector pumps? Thanks.

Topic

[firehoser75]

NoSpeed,
Your boat and your call, but if it was me, I would not want to risk further damage to the engines or even the new components you are just installing to gain a month or so of boating time. Bayliner is a popular make, so I would guess that any place that does a lot of exhausts has probably already done these before, which may shorten the timeframe.
JMHO
Good luck with whatever you finally decide,
Tom

[NoSpeed]

Steve, yes, these are Genuine Holset Turbochargers shipped by UPS ground from their Headquarters in Memphis TN. They had 13 of my model in stock. I am willing to accept a delay due to the more reasonable ground shipping charges, but this will add about 4-5 days to the turnaround time. This model is the HX-40M. The quoted price is before tax and shipping. I will have to paint them. They come with all the gaskets, which I had previously ordered from SB Marine, and will now have to return.

Tom, I am sure Tony, or someone on his team, knows if there is a better solution for my Exhaust Risers. However, I am anxious to get the boat ready for this year’s cruising season, which begins on 7 Feb. I will probably be forced to use the existing risers until I can find a more permanent long-term fix. Thanks for all your suggestions.

[firehoser75]

New Exhaust

Hi NoSpeed,
If I were you, especially now knowing that the existing exhaust system is the root cause of all (at least most) of your issues, and the fact that you are located in California, I would contact Seaboard for help and a quote (probably by phone where I could get more complete info and provide more complete info to them). Obtain other quotes if that is something you would find important.
Best of luck and I hope that all of this doesn’t “break the bank” (ouch for sure),
Tom

[Stephen Oliver]

$1295 for new turbos? Wow.. are they genuine holset? That seems very cheap (in Aus they are over 3k!) Hence me getting rebuilds

Steve

[NoSpeed]

The turbo shop has reported back to me the repair would cost about $300 more than replacement with a new one. Consequently, I ordered two of them ($1295 ea.). As for the exhaust riser, I guess we can conclude it is at the root cause of my issue. All of you seem to be in favor of me finding a custom exhaust solution, rather than reinstalling these. The only thing in my favor is that I now cruise mainly in freshwater. I have no idea what will work in that space because of the 12″ minimum space requirement above the spillover point, which is only an inch or so below the base of these riser cans. Anybody here found a solution to this issue in a Bayliner 47? Thanks.

[Stephen Oliver]

Not as bad as mine were – but still obvious from the rust, flaking and rust ‘droplets’ everywhere that its been washed by saltwater frequently.

There is no carbon build up as such – its a flaking housing – remedy is to overhaul the turbo fully – by someone that know what they are doing with marine holsets, the housing should be recoverable by machining and sleeving the exhaust outlet. Machine the flange face also. The turbine may or may not be ok, the turbo shop can check and replace the turbine if needs be.

For me the good news was no evidence of rust in the manifold so I had been lucky – worth having a good look in yours when you pull the turbos.

Tony has some good pictures on here of good and bad turbos. Have a look at my previous posts and you will see a real bad turbo that was still operating, but how I do not know.

Put those risers back on as everyone else has said – you will be doing this whole thing again in a few years when the turbo’s have rotted out again…. I’m in the process of replacing my standard cummins elbows for safer risers but my mufflers are an issue too due to water level – so I drain them on shutdown.

Steve

[firehoser75]

Turbo Condition

NoSpeed,
If you desire the help that Tony and his staff offer “FREE of CHARGE”, please take the time to actually listen to their suggestions and questions and provide the answers as requested. Just because you already provide some of the info in an earlier post, you cannot expect that Tony or staff have read your earlier posts recently or that they have the time, when offering free advise (to many), to re-read those posts. As much as from your point of view you may have “already done that”, it is just best if you “do it again” (providing info).
If you have followed this forum for any time period, it will be apparent that there are alot of mechanics out there (including so called “factory installs”) where the work could have been “better performed”!!
FYI, I agree with Brian, your turbo does not look good. It has been subject to salt water. I would have large suspicions about your exhaust setup and it’s condition, to say nothing about the turbo or the engine (head area).
Not trying to upset you, just trying to point out a different point of view.
Good luck,
Tom

[Brian Katz]

Turbo condition

I’m new to these engines but what I’ve read and seen here suggests that your turbo is indeed suffering from water ingestion from poorly designed “risers.”

I wouldn’t be comfortable putting those back in the boat. An ounce of prevention is definitely better than a pound of cure.

[NoSpeed]

Today, I dropped off the turbo at the shop. They think the issue is probably related to an excessive build up of carbon on the exhaust side, causing a restriction in air flow. They can blast it off. The exhaust riser did not have any similar build up of carbon. It is in good shape and reusable. The bolts had to be cut-off. The coolant failing to gravity feed is still a mystery, however with the 2nd removal of the drain plug, coolant was flowing freely. I installed a petcock. The plan is to put the port engine back together with new coolant, heat wrap and gaskets/bolts/washers. A sea trial will be conducted before removing the starboard turbo. Pictures of the exhaust riser and turbo exhaust prior to cleaning are attached. Thanks.

[NoSpeed]

Rob, yes, I was able to get squarely on 3 of the 4 bolts with the impact wrench. Tony, my mechanic is terminally ill and has gone out of business. I have read your article. Regarding #3, you are correct. Regarding 1), if you mean at rated RPM, this has not been done since a Sea Trial in May 2013. Data has been lost over time. 2) I previously answered that question. 3) My mechanic did perform WOT to 3141 RPM at the dock in neutral and was able to detect the sound of a bad injector. He did believe my issue might be fuel related and intended to return to replace a diaphragm in the fuel injection pump before he became ill. Also, he recommended replacing the exhaust riser bolts in the near future. 4) Yes, both engines start clean, easy and quickly when cold. 5) Aftercoolers were just cleaned per your protocol. Before pics are on a previous page. How do I move forward from this point? Your advice is much appreciated. Thanks.

[Tony Athens]

This post is so classic of an owner seeking advise of a his “mechanic” after asking him to investigate a performance issue only to find out that after spending maybe $3000 +, nothing was fixed..

#1———Get a new mechanic, as with the symptoms you have posted, injectors is 100% the least likely issue causing exactly what you described. Your mechanic has no clue about how an engine like this operates & then diagnosing symptoms when it does not operate right. Maybe you leaving something out so I am critical without knowing all ??

#2———-Have your mechanic read this a few times—You read it too..

https://www.sbmar.com/articles/understanding-low-power-troubleshooting/

#3—— How many of the items listed in the article were properly looked at related to the issues you described BEFORE he replaced the injectors? I’d guess zero on the ones related to low power & dark smoke.

So now that we are past that, IF what you posted is accurate & nothing has been left out, this is how the problem should have been sorted out or how a solution to thos should have gone forward.

1) When was the last time you took your vessel to WOT running at the weight you run about at, and then made a note of the RPM and vessel speed you reached?

2) When was the last time your vessels bottom & running gear were cleaned to close to “baby-butt” smooth? Or, just had good once a month or so bottom cleaning, prop & running gear cleaning?

3) WOT RPM at the dock in neutral has nothing to do with your issue—If your mechanic thought otherwise, this is just another reason he does not belong in this business in this capacity for diagnosing an issue like this. Checking it is good, but again, would not be related this this issue.

4) . Do your engines start clean, easy, & quickly when cold (after not being run for a few days) ?? If so let me know, as that usually eliminates some other potential issues.

5) When was the last time your aftercoolers were removed from the engines, put on a bench and serviced per my protocol? This is super important to know.

6) As to the “other” recommendations by him , at this point is this, just a 100% “money stream” for deposit into his wallet

Come back and answer or comment effectively all I have asked r mentioned.. Then we can go forward from here.

Tony

[Rob Schepis]

With an impact wrench? Firstly, tasks like these are all about “finesse” (surgery, so to speak) and secondly I am suprised you could even get an impact squarely on there?

[NoSpeed]

This weekend, I attempted to extract the exhaust elbow bolts after a generous application of penetrating oil and soak time. I used Rob’s suggested Craftsmen bolt extraction tool set: http://www.searshometownstores.com/product/Craftsman-52166-10-pc-Damaged-BoltNut-Remover-Set?store=&preview=3114&isClearanceItem=F&utm_source=google&utm_medium=cpc&adpos=1o3&utm_campaign-SC%20Shopping&scid=scplp39959097&sc_intid=39959097&gclid=EAIaIQobChMI69uQp7ul3wIVNR6tBh1uIAX0EAQYAyABEgIm3_D_BwE with an impact wrench. Unfortunately, it resulted in rounding off the heads of two of the four bolts. So, I stopped trying and left the other bolts alone. It appears my next step will be to use a grinding wheel to cutoff the heads. To extract the studs from the turbo housing seems best done with the turbo off the engine. I think it may be in my best interest to take the turbo to a shop for the best chance of extracting what will be left of these bolts. Consequently, I am thinking ahead to the next step in the process. I am aware the coolant must be drained from the engine in order to proceed. Since the coolant is old, it might as well be replaced. Currently, the engine has a green colored coolant and I was thinking of moving to a red colored coolant, like Fleetguard ES Complete OAT. So, I got everything ready to drain the system. I started by removing the drain plug: https://www.sbmar.com/wp-content/uploads/2015/09/B-series-Coolant-Drain.jpg . I had the pressure cap off, but when I removed the drain plug, not a single drop of coolant came out! This was a total surprise. Please clue me as to the right path. Thanks.

[Stephen Oliver]

The bolts are not as bad as mine were on the SB side – I ended up removing the turbo (as I knew it was shot) and taking it home so i could work on it. I got 2 of the 4 out.. but the other 2 i had to grind off (elbow was shot too) with a bit of heat I managed to remove one of the 2 stuck ones.. and the final one I gave up with. The guy that sleeved the housing also had to machine the face etc.. so machined over it, drilled it out and re tapped it.. it was little more work than he had to do anyway.

The port turbo that was even more gone than the SB one but the bolts came out as someone had had them off recently to bog up a leaking exhaust (because the housing was so badly corroded) – interestingly they were stainless – but not a chance I would replace them with stainless. The SBMar bolts have big heads and the washers are ultra thick – so they dont bend into the slots..

Steve

[NoSpeed]

OK. Will do. Thanks.

[Rob Schepis]

No on the SS, Just install all with never sieze.

1 user thanked author for this post.

Tony Athens

[NoSpeed]

Excellent! And, what about the merits of my SS washer idea? What type of washer material is used with the bolts you sell?

[Tony Athens]

I mis-spoke……10.9 Alloy bolts x 8mm

We have 12.9 for some other sizes and fine threads..

Tony

[NoSpeed]

Rob, you are correct. The bolts are M8x1.25×25 and are sold at Bolt Depot in class 10.9 for $0.30 each. Here is a link: https://www.boltdepot.com/Product-Details.aspx?product=17503 I feel so ripped off by Cummins. I will be sending those parts back for a refund. Unfortunately, Bolt Depot does not carry this metric flange bolt in class 12.9. I am unsure where it would be found, unless Tony has them. I speculate the backside of that flange is rusted to the washer, which is why the torque required to break them free is so great. Would there be anything wrong with using the zinc plated class 10.9/12.9 steel flange bolt replacements with stainless steel 18-8 or 316 plain washers? Anti-seize lubricant on all the bolt threads, of course. This way, there would be no chance of the steel bolts rusting themselves solid to the washers years later. Wouldn’t this be the best solution? Bolt Depot has the SS washers for just $.10 each: https://www.boltdepot.com/Product-Details.aspx?product=23030 BTW, I ordered a set of those Craftsmen bolt extraction tools you recommended. Thanks.

[Rob Schepis]

The bolts are not 10MM, they are 8MMx1.25(coarse). Whether they are grades 9.8, 10.9 or 12.9 is really not the ultimate issue here – it’s all about proper installation and controlling the environment that they are subjected to.

[Author]

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