8.1 petroleum spots in exhaust

SeadawgVB

SeadawgVB

Active Member
Jul 8, 2013
411
Tidewater Virginia
Boat Info
2004 480DB
Engines
QSM11
You may have read thru my other thread http://www.clubsearay.com/index.php?threads/calling-all-8-1-gurus-running-rich.87838/ where I was under the impression that poor spark may be the cause of my engine running rich showing petroleum product spotting in the exhaust. I say petroleum product because I'm not 100% sure it is gasoline, I'm like 85% sure it's gasoline.

Well, the plugs and wires have now been swapped and it's still doing it. (Even after running for five hours over the weekend, so I know the residuals should have been flushed out of the exhaust.)

No water in Engine or transmission oils, antifreeze level is unchanged.

I'm also following a thread on "SeaRay Owners" page on Facebook where another person is having this same issue and two more folks indicating similar issues, so it seems not crazy uncommon.
By the way, I have cool fuel II, so it's most like not a cool fuel paint issue.

Next steps (in my mind):
1. Check fuel pressure as recommended by Scoflaw.
2. Send of injectors for cleaning / flow testing.


Questions to you folks, What else could it be? Any "next steps" that you would add to my list above?

Thanks for reading.
 
Probably need to do a compression test on all cylinders, if not an option, get a thermal laser temp sensor, and while engine is running, check each exhaust port on the manifold for significant temp change in exhaust gas. Will point you to the right cylinder at least
 
I had a similar issue on my last boat. It ended up being a trim hose leaking. Completely unrelated to the engine.
 
Basically, if fuel is off the table......any of the heat exchangers that are raw water cooled are suspect. Oil, Transmission and Cooling are all possibilities. Usually you notice the fluid levels dropping and can't figure out where the fluid is going.
 
PlayDate said:
Basically, if fuel is off the table......any of the heat exchangers that are raw water cooled are suspect. Oil, Transmission and Cooling are all possibilities. Usually you notice the fluid levels dropping and can't figure out where the fluid is going.
Click to expand...

Fuel is not yet off the table, in fact it is still the lead suspect. Fluid levels are not changing and oils are not affected by water. There is a difference in engine oils (color wise) and I think it may be fuel contamination. Since I've heard a few "me too"s on Facebook, but the only resolution anyone has offered was the same as Creekwood above (He may have been the poster on Facebook as far as I know), trim tab fitting on the exterior of the hull was leaking. I have not checked the tab reservoir lately (but I will this weekend), but doesn't fit with the engine oil discoloration.

I also plan on checking fuel pressure on the rail to see if it is in spec as well.

I'll keep you all informed.
 
speaking of it seadawg, have you experienced good results with removing and cleaning the injectors? Im in the middle of a backlash noise that lead to injector removal and paint flakes which Merc refused to warranty - 3K quote per engine to replace and 45$ to clean - doing impellers at the same time. I am new to this one and by no mean hijacking just inquiring. thanks I would rather be out on the water.
chris
Happy 4th to all!
chris
 
Latest update: Cycled the trim pumps many times to rule out any leakage on the out side of the boat as Creekwood suggested; nothing found. (I was shocked at how little those tabs actually move, only about three- four inches of deflection.)
Did the fuel rail pressure test; 40 PSI key on, 35 PSI engine running.
 
Fuel Cooler Leak?
 
Latest update: Went for a longer couple of cruises this past week. I noticed the "petroleum spots" had been becoming more like an actual sheen while at idle during docking maneuvers. Upon checking the oil (which I check EVERY time for color, water and level, before leaving my dock) before my last leg, for the first time I noticed a change (drop) in the oil level compared to the starboard motor.

SOOOO.... Maybe my fuel droplets are actually oil! (Actually, most likely oil!) Due to the fact that the oil pressure is ALWAYS more than the water pressure, oil must be slowly seeping out of the oil cooler. After googling "8.1 oil sheen in exhaust" everything points to the oil cooler. Ordered new oil cooler from Mr. Cool, should be here tomorrow.

Now the big question, should I begin replacing ALL the coolers / exchangers on both engines. I know these motors will last a long time if I can keep the cooling water where it is supposed to be.

I will test the original cooler and if / when I find the leak in the oil cooler, I will replace the starboard oil cooler as well.
 
They are 15 years old and you are on salt water. I would replace the oil coolers and the transmission coolers if you haven't already. They are cheap insurance compared to what they protect.
 
Final result: Swapped out the oil cooler from Mr. Cool. (It was a perfect fit replacement!) Biggest challenge was getting the hoses to release and to get the oil lines swapped without spilling oil everywhere. Ran it for four hours this weekend, no more petroleum spots coming out of the exhaust!!!!

Of course during these last couple of months I've been noticing this same engine (port side) the temperature has been has been creeping up during cruise on a plane (3200ish rpm) compared to starboard. So I have my next rabbit to chase down a hole. I'll start a new thread on this one.
 
PlayDate said:
They are 15 years old and you are on salt water. I would replace the oil coolers and the transmission coolers if you haven't already. They are cheap insurance compared to what they protect.
Click to expand...

Playdate, that's your theory on replacing the transmission oil coolers? I had a leak on my starboard transmission oil cooler that caused a transmission failure. I asked the mechanic if I should replace the port side cooler, he said "it's optional, but that a leaking transmission oil cooler was not a very common failure".

Thanks for your thoughts!
 
TexasBryan said:
Playdate, that's your theory on replacing the transmission oil coolers? I had a leak on my starboard transmission oil cooler that caused a transmission failure. I asked the mechanic if I should replace the port side cooler, he said "it's optional, but that a leaking transmission oil cooler was not a very common failure".

Thanks for your thoughts!
Click to expand...
I guess it depends on a couple of things. How much were the repairs to the transmission (or replacement) compared to a new oil cooler? It could have been a manufacturing defect that caused the failure, or it could have been a "time in environment" type of thing. My oil cooler failed on my port motor, I plan on changing the other after this boating season; cheap insurance.

I see Mr. Cool has replacement tans oil coolers for Cummins from $250 - $800 dollars. Call them with your trans details and they will tell you exactly which one to buy.

http://www.mrcool.us/coolers/cummins/cummins-coolers/cummins-transmission-gear-coolers.html
 
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