Yanmar 4LHA STEs Black Smoke 1800-2000 Rpm — 2001 Albemarle Express

[Kenneth Athans]

I’m experiencing black smoke from both of my engines ONLY while trolling in the 1800-2000 rpm range. Boat seems to be plowing through the water and putting strain on engines. No smoke at idle or when the boat gets up on plane. My friend has the same engines and 2002 Albemarle 280 express. He has about 600 hours on his engines and just replaced the turbos. He is experiencing the same black smoke issue in that rpm range.

I purchased the boat used four months ago and have a good history of maintenance from the Yanmar tech who worked on the boat for several years here in Hawaii. Engines have 2380 hours on them. Tech replaced both turbos and exhaust fittings and cleaned lube oil and after cooler just prior to me purchasing the boat.

I have done the following maintenance after purchasing:

— Repainted the bottom and cleaned running gear
— Changed shaft seals and strut bearing. Aligned both engines to the shafts.
— Installed dual racor fuel filters and changed secondary filters on the engines. Use 10 micron elements as my primary filters.
— Replaced both impellers, sea waters strainers and raw water intake hoses
— Installed fresh water connections and flush engines with fresh water after each use
— Cleaned transmission oil cooler
— Replaced all zincs on both engines, shafts and hull
— Cleaned fuel injectors and shimmed back to specs
— Changed the oil & filters 60 hours ago on both engines. (I noticed it gets black pretty quick & not sure if this is normal or related to black smoke)
— Replaced crush gasket on port engine exhaust elbow to fix exhaust leak
— Replaced stock Yanmar turbo filters with the after market ones Tony recommends
— Turbo washed both turbos with Yanmar turbo wash

I’m leaning towards this being a prop issue since the engines seemed to over worked at the 1800-2000 RPM range. May be the cupping wearing down over time. Props are 18×18 with medium cupping.

Any thoughts/recommendations based on similar issues with these engines would be much appreciated.

Topic

[Bill Fuller]

Ken,
You don’t need to run the boat at WOT with a photo tach hooked up. I think you already had the info I was asking about. I am just a bit confused on your reading, probably all on my end. You already gave the info, but could you list
Tach = 3300
Strobe = ?
With 4 blades you may well be a bit over propped.
If you look at the spec sheet Rob posted you will see that Yanmar would like to see these engines turn up 3450 to 3550 RPM under a full load at WOT.
I would like to hear Tony’s take on the 4 blades vs. 3 blades for your boat.
Dave and Jeff both work in the fisheries industry, both research and commercial, out of Oahu.
FYI, my 28 Bertram with the same motors as yours was set up by Tony with18x18, 3 blade Nibral props.
Boat easily made the Yanmar spec. my props were damaged when I had a half tower built back in 2002 and the props are now 17.5×18.5. Made virtually no difference in the original performance. I am now at 5,231 hours.
Same turbos, injectors, etc. etc.
Thanks
Bill

[Rob Schepis]

Accurate RPMS

You do not need to be in the engine room underway. This is all done in neutral at the dock. Make up a sheet like this and keep it at the helm – just fill in the ?’s

[Kenneth Athans]

Thanks Rob and Bill!

— Due to the tight engine compartment I don’t have a way to measure WOT loaded but it does seem the analog tach
is a bit off. WOT jumps between 3250 and 3350 loaded on my current dash tach setup. The only way I’ll be able to
measure is with some sort of proximity switch connected to a digital gauge to measure unless you know of a better
way.
— Yes, 2001 Albemarle 280 Express
— 4 blade props and ratio is 1.586:1
— I use trim tabs but they don’t seem to help in that RPM range

I haven’t run into Dave Itano or Jeff Muir. Do they operate out of Oahu?

Thanks,
Ken

[Bill Fuller]

Hello Ken,
I have a few questions. I assume your boat is a 28 foot Albemarle.
Is it also an express?
Since you are running 18×18 props, I assume 1.5/1 gear ratio, correct?
Are your props 3 blade or 4 blade?
As Rob asked, as it was not quite clear to my old eyes/ears, when your tach reads 3300, what does the photo tach read?
Do you use trim tabs?
That 1800-2200 RPM range is a difficult one to deal with as the boat is trying to climb up on plane, and turbos are not really spooled up yet. How fast are you trolling?
On my 28 Bertram, I usually try to keep the trolling speed at 1500 or less (7-8 knots), same engines and setup as your.
Just a curiosity, you ever run across Dave Itano or Jeff Muir over there?
Bill

[Rob Schepis]

As to your answer D – So, based on the above 3,300 on the dash tach is really 3,400 on the engine ??

As to your answer E – You state 3,300… is that on the dash tach or the phototach?? What is the phototach rpm on the engine at WOT loaded??

Here is the Yanmar propping specs to include your engine.

(BTW, Ken when I did a quick edit and restructure of your post for better readability I had to repost under my name)

[Rob Schepis]

Ken posted new info. I restructured the format and had to re-post under my user:

Kenneth Athans wrote:

Here are the list of answers to your questions.

A. At what speed RPM & vessel speed does the vessel get up on a clean plane?

2300 rpm @ 12-13kts

B. Does the vessel struggle at all getting up on plane–meaning you have to give it most of all it’s got to get it up on top, and then back off?

Not all…turbos spool right up and black smoke goes away as boat gets up on plane.

C. When getting up on plane, do you see any black smoke?

No

D. Ever verified your tach accuracy–I.E. 3000 on your tach = what real RPM on a strobe?

Tach was 100 rpm lower at the dock at 3300 rpm.

E. What is you WOT RPM on the tach “loaded “as you use the boat.

3300 RPM

F. EXACTLY why were the turbo replaced at such low engine hours?

Turbos were replaced on my boat because the previous owner allowed rags to get into the oil system which blocked oil lines to turbos. Mechanic took the lube oil cooler out to be cleaned and owner stuffed rags in the lines to prevent dripping and never took them out prior
to the mechanic putting things back together.

I’m looking to get better performance/efficiency in the 8-10kt range because that’s where I spend most of my time trolling. I don’t care about top end speed as I rarely push the boat that fast. Props are stock and 18×18 with medium cupping.

Yanmars also have a boost compensator adjustment and not sure if that would help my situation along with going to an 18×17 or even 18×16 prop with medium cupping.

Appreciate the advice from all in helping me work through this issue.

Kenneth Athans

[Kenneth Athans]

Here are the list of answers to your questions.

A. At what speed RPM & vessel speed does the vessel get up on a clean plane?

2300 rpm @ 12-13kts

B. Does the vessel struggle at all getting up on plane–meaning you have to give it most of all it’s got to get it up on top, and then back off?

Not all…turbos spool right up and black smoke goes away as boat gets up on plane.

C. When getting up on plane, do you see any black smoke?

No

D. Ever verified your tach accuracy–I.E. 3000 on your tach = what real RPM on a strobe?

Tach was 100 rpm lower at the dock at 3300 rpm.

E. What is you WOT RPM on the tach “loaded “as you use the boat.

3300 RPM

F. EXACTLY why were the turbo replaced at such low engine hours?

Turbos were replaced on my boat because the previous owner allowed rags to get into the oil system which blocked oil lines to turbos. Mechanic took the lube
oil cooler out to be cleaned and owner stuffed rags in the lines to prevent dripping and never took them out prior
to the mechanic putting things back together.

I’m looking to get better performance/efficiency in the 8-10kt range because that’s where I spend most of my time trolling. I don’t care about top end speed as I rarely push the boat that fast. Props are stock and 18×18 with
medium cupping.

Yanmars also have a boost compensator adjustment and not sure if that would help my situation along with going to an 18×17 or even 18×16 prop with medium cupping.

Appreciate the advice from all in helping me work through this issue.

[Tony Athens]

I’ll wait for all, but for sure get you tachs verified at the dock, in neutral at 3000-3200 RPM.. Write it down..

Tony

[Kenneth Athans]

Thanks, Tony. Here are a few answers below. The rest I’ll observe when I take the boat out later this week.

B. No struggle at all to get up on plane

C. No black smoke at all after getting up on plane…nothing but a nice clean wake.

D. I’ve never verified tach accuracy

F. Turbos were replaced on my boat because the previous owner allowed rags to get into the oil system which
blocked oil lines to turbos. Mechanic took the lube oil cooler out to be cleaned and owner stuffed rags in the lines
to prevent dripping and never took them out prior to the mechanic putting things back together.

[Tony Athens]

Ken,

Let’s tackle this another way…………….Answer these as best you can..

1) Loaded as you use the boat, what are the following numbers/answers–Be as accurate as you can.

A. At what speed RPM & vessel speed does the vessel get up on a clean plane?

B. Does the vessel struggle at all getting up on plane–meaning you have to give it most of all it’s got to get it up on top, and then back off?

C. When getting up on plane, do you see any black smoke?

D. Ever verified your tach accuracy–I.E. 3000 on your tach = what real RPM on a strobe?

E. What is you WOT RPM on the tach “loaded “as you use the boat

F. EXACTLY why were the turbo replaced at such low engine hours?

Let’s start with these ??’s..

BTW, the “HUMP” thing Rob mentioned is what is going on, but I want to see if we can mitigate that some..

Tony

[Kenneth Athans]

Attached is a pic of the engine turbos and exhaust elbows minus the new turbo filters I just installed to replace to stock Yanmar filters. My friends boat has only 600 hours and turbos got corroded pretty bad due to the boat not being operated for several years.

I agree with the boat/installation thing and I’m waiting for a call back from Albemarle regarding prop issue to see if they have dealt with this before. I’m ready to replace the props but just want to figure out the best pitch/cupping given the issue.

[Rob Schepis]

Any pics of the engine installs especially including the exhaust?
600 hours and turbos replaced?
Sure sounds like boat/installation thing, not an engine thing..
Cup = theoretical pitch = load….. loss of cup is not your black smoke issue.
Looks like you are running at the hump speed that deep V hull does not want to be at..

[Author]

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