Gray smoke and algae?

We started our northern portion of the loop a couple weeks ago with a goal of having the boat here in Tennessee before winter.

From the start, both Lehman 135s produced more gray (not blue gray) smoke than I’ve seen before. I talked to Brian Smith, who basically said the cause was hard to determine and that he wasn’t too worried about it.

We ended our first leg in upstate NY where I had the boat hauled to check a vibration. While there, I thought I’d get a mechanic to check the idle on both diesels which has been rough.

The mechanic said we have algae in the fuel and sent me a photo. This was a surprise since I run out of a day tank and any fuel going through the engines is filtered through a paper towel roll filter before it goes into the day tank. He said the engines are starved for fuel. He wanted to polish the fuel, change out the primaries and secondaries and add Biobar — then sea trial it to see if that stops the smoking and if it improves the idle.

I changed out all the fuel filters 70 hours ago. The aft day tank is clean. I saw almost no vacuum on the Racor gauges while underway and I wonder if fuel starvation is the right diagnosis.

That filter is very clean.

I have seen them black and dripping slime and still the engine would run OK.

Now, restriction could happen from the aqua Bloc treatment that filters out water, but that's something I am not all that familiar with causing a restriction.

That does not look all that bad to me. I have seen much more loaded filters where the engine still runs fine. And with no vacuum issues according to your Gage's that backs that up.
I question his diagnosis also.

I dont think clogged filter could cause grey smoke.

Are you sure that it is not steam or water vapor???

bayview said:

I dont think clogged filter could cause grey smoke.

Are you sure that it is not steam or water vapor???

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Thanks. It’s definitely grey and the engine temps are a stable 180 at 1750 rpms.

psneeld said:

That filter is very clean.

I have seen them black and dripping slime and still the engine would run OK.

Now, restriction could happen from the aqua Bloc treatment that filters out water, but that's something I am not all that familiar with causing a restriction.

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jleonard said:

That does not look all that bad to me. I have seen much more loaded filters where the engine still runs fine. And with no vacuum issues according to your Gage's that backs that up.
I question his diagnosis also.

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Right. I’ve seen clogged filters on these engines before I had the tanks cleaned and they were solid black. Plus, as I noted, the Racor gauges barely move off dead bottom while underway.

Hate to say it but I’m wondering a little about what to trust here.

angus99 said:

Right. I’ve seen clogged filters on these engines before I had the tanks cleaned and they were solid black. Plus, as I noted, the Racor gauges barely move off dead bottom while underway.

Hate to say it but I’m wondering a little about what to trust here.

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Some tech expert will surely chime in and I am not one but grey smoke + rough at idle, may this come from injection pump issue?

L

Pump or injectors would be a guess grey smoke could be unburnt fuel imo.

Thanks. Injectors were serviced about 100 hours ago. Secondary filters were spotless when I replaced them 70 hours ago, but I don’t know much about what can do wrong with the pump.

Filter looks fine. Way better than mine when I change it.

Fuel restriction usually starts showing up as unsteady rpm at high power, but ok when power is reduced.

Grey smoke could be simply steam!! Does the smoke (or steam) dissipate like ten feet behind the boat? Or does it linger way back in the wake and make your eyes burn? Steam dissipates, smoke does not.

And what is this about a rough idle? All these engines shake at dead idle, sometimes the mounts isolate this normal vibe from the boat, some mounts allow the engine to rattle the boat at dead slow. That is not an engine problem, it is normal.

But a rough idle could mean a misfire, that is a much lower frequency, more like a "lumpy" engine.

Post a vid showing your "rough idle".

Ski in NC said:

Filter looks fine. Way better than mine when I change it.

Fuel restriction usually starts showing up as unsteady rpm at high power, but ok when power is reduced.

Grey smoke could be simply steam!! Does the smoke (or steam) dissipate like ten feet behind the boat? Or does it linger way back in the wake and make your eyes burn? Steam dissipates, smoke does not.

And what is this about a rough idle? All these engines shake at dead idle, sometimes the mounts isolate this normal vibe from the boat, some mounts allow the engine to rattle the boat at dead slow. That is not an engine problem, it is normal.

But a rough idle could mean a misfire, that is a much lower frequency, more like a "lumpy" engine.

Post a vid showing your "rough idle".

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Thanks, Ski.

I’ll video the steam/smoke when we’re back at the boat. I think it dissipates 10-15 feet behind. I had always thought a properly tuned Lehman ran “clean” after warming up.

The idle seems to hunt just a bit at dead low throttle and the boat shakes more than I remember. OTOH, we did install new mounts prior to noticing this. I may try increasing the idle speed as discussed above.

Your filters aren't bad, carry spares.

I've been running diesels about 60 years. Old fuel, if that's the problem, can cause smoke and unburned fuel. If the engines ran fine last season it's probably old fuel and gummed up injectors. Using a decent additive will clean the injectors and make the fuel burn better (hotter). Eventually new fuel will solve the problem.

To me, fuel polishing is just the latest money making scam. I use a conditioner every fueling and never have fuel problems. If you want to clean the fuel, and your engines don't have a high return fuel flow, add a circulation pump that pulls thru the filter and returns to the tank. There are 12v electric pumps on ebay for about $10 that pump 20-30 gallons an hour. With an additive, run for several hours, run with or w/o the engines. You want to filter the fuel several times. Your primary filters should be rated for a flow much larger than your engines use. If you really want to clean, after the initial clean, put in a 2 micron filter. I run 2 micron all the time. There are advantages to having super clean fuel - longer injector and pump life.

I use Archoil 6200, available on ebay or Amazon (or Archoil.com). 1 oz/80 gallons, but with old fuel or a dirty tank 3 oz/80 gallons. It burns fuel better and also gives me about 7-8% better fuel mileage. I also run in my Ford diesel 3/4 ton, 4x4 and routinely get 20-25mpg at reasonable speeds.
If you ad an electric in line to each of your engines, it makes changing fuel filters and bleeding much easier. Added inline, the normal lift pump will pull thru with the electrics off. In the event of a lift pump failure, turn them on and you're back in business.

Thanks. My antennae definitely were up when fuel polishing was suggested—particularly since I filter the fuel before it goes in the day tank.

Just got the mechanic’s bill—minor rant

Just shy of $800.

This was to replace two primary and four secondary fuel filters, clean the bowls and add Biobar. No other work performed over the 5 hours he was “on the boat.” Mechanic’s report says the filters were “full of algae.” See photo above.

Also included was $160 for travel (18 minutes one way from shop to boat).

I made the mistake of authorizing the filter replacement without getting a time estimate and not being present to monitor the work—so that’s on me. Thought it would be one less thing to deal with when we returned to the boat (which we just did). I’ve done this work before and know what’s involved; it can be done in two hours max. I called the owner to question the charges and he said he’d review the bill.

I’ve paid untold thousands to specialists for work they could document without batting an eye—and I expect to pay for services received. Am I the only one who thinks this guy should be wearing a mask and carrying a gun?

If the guy hourly rate is 400$/h the total make sense

L

..."He wanted to polish the fuel, change out the primaries and secondaries and add Biobar — then sea trial it to see if that stops the smoking and if it improves the idle."




Considering the previous bill, this work would put you in the Emergency Room!


Nothing too wrong with that filter. Red Alert!
Unless you have a cloud following you, move on.
Oh yea, check your air intake flow path.

bayview said:

I dont think clogged filter could cause grey smoke.

Are you sure that it is not steam or water vapor???

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Angus99, I had a similar concern on the Canadian waters but, as suggested, it turned out to be steam generated by the exhaust AFTER exit from the boat. Now that we are on the Illinois River, no steam, no colored exhaust. The steam clue was that both engines were doing the same.

Hi, Tony's write whithe/gray smoke, maby this help you, i hope.


https://www.sbmar.com/articles/what-is-white-smoke/

Could it be too low cetane% your fuel? Cetane booster supplement agent could help better combustion and higher temperature in cylinder / engines?

NBs

angus99 said:

Thanks. It’s definitely grey and the engine temps are a stable 180 at 1750 rpms.

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Hi,

Is the temperature of the boat's meter or have you checked it for example with an IR meter from the block and other engines

NBs

First of all, all Lehmans have a "sweet spot" for idle, if you get off that they'll shake like dog with a rat in its mouth. Just tweak the power levers until they are smooth. Secondly, the grey stuff is steam, the ambient temps have fallen and you are putting warm exhaust water in colder water now... this topic comes up every Fall.

IMHO, you have been screwed by the mechanic, get him off your boat and pay him half. Let him document his work and try and recover from you as you sail off into the horizon.

Thanks all.

To answer NBs’s question, I do check engine temps with an IR thermostat at multiple locations hourly while underway and they’re always consitent. Thanks for the Tony Athens article. I’ll read it while we’re underway tomorrow.

We’ll be entering the Illinois in three days, Jack, so I hope we see the same change.

Xsbank, I adjusted the idle down a bit to about 600 and that’s helped a lot.

Are you operating at the usual cruise RPM, or have you pulled back in rivers or canals?

Temperature does not seal the piston rings , load does .

FF said:

Are you operating at the usual cruise RPM, or have you pulled back in rivers or canals?

Temperature does not seal the piston rings , load does .

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Usually running 1650 to 1700 rpms, which seems to be a sweet spot for speed and fuel economy. Still seeing what I understand now to be steam, trailing 15 to 20 feet behind the boat and dissipating. Almost no vacuum on the Racor primaries.

Any mechanic who says there is algae in the fuel is clueless. Algae simply cannot grow in diesel.