Fuel Sheen

[Lew]

Hi there. I just got my aftercoolers back from SBMAR, and put them back on, I was told they were cleaned and pressure tested. I also just finished installing SBMAR CCV kit (thanks Justin). My question is Starboard engine seems to have lots of fuel coming out exhaust and making sheen on the water. Didn’t really have that prob before, and port Engine not doing it? 98 6BTA 330 aprox 2300 hours , new injectors about 3 years ago.

Thx for info- Lew

Topic

[Lew]

thx for info

[Richard Dodson]

The nose knows

Start the engine or after running it. Put your hand where the exhaust water will hit it,  remove and smell hand. If it smells like diesel, fuel cooler (I see you have eliminated the injectors). If no smell, perhaps the gear oil cooler.  30 WT motor oil or ATF doesn’t smell.   FWIW, a local very reputable diesel shop just rebuilt a friend of mine CT6A 450, brand new injectors from Cummins . During sea trial, one injector tip cracked, over a gallon of fuel into the crankcase. The point is, even new injectors can fail.    

[Lew]

Thx Bill

[Bill Desmarais]

Back ten years ago or so I owned three brand new 6BTA 370s with gears.

Obtained by  Seaboard Marine and “tricked out”  before shipping to me.

All three had the fuel coolers removed, Envirovents installed, idler pulley upgrages and greased after coolers from Seaboard.

All three were under propped from hour number one.

I boat up in the northeast with cold waters.

Each of the three 6BTAs from new had very light sheens of fuel in the exhaust flow, hot or cold. In the sunlight. 

I always attribured this to unburnt fuel. Mechanical diesels 

[Lew]

Thx Woo,

 I just got a new gear oil cooler, I think Ill just put that on and take it for a spin. A friend mentioned this could be from the grease that was put on after cooler when they were assembled? IDK. For now Ill install new cooler and run the boat then report back. Then maybe start looking at the injectors, but boat sounds and runs smooth so?

thx for info

[Lew]

Dave, So was the problem your oil cooler?

thx 

[Woo]

Good lateral thinking there David.

“So place fitting where cooler should ben be, and then check exhaust should be clear? correct? just raw water” – Correct Lew. Try this, or, you may find it easier to use David’s method.

Bear in mind, if you still have the fuel cooler, it could be that too.

[David Amble]

I recently had a similar problem (different engine to yours) with an oil sheen coming out of my port engine exhaust.  After eliminating the possible fuel sources, I bypassed the water side of the transmission oil cooler and started the engine.  This put normal gear oil pressure on the cooler and I was able to look into the water side.  Bingo!

1 user thanked author for this post.

Rob Schepis

[Lew]

So place fitting where cooler should ben be, and then check exhaust should be clear? correct? just raw water

thx for the response

 

[Woo]

Tony means to get a fitting to join the two gear cooler lines together, taking the gear cool itself out of the circuit. <br />Only at the dock, as the gear won’t be getting cooled (obviously).

[Lew]

Im sorry, I know this might sound stupid to you. what do you mean (flare union).

thx again 

[Tony Athens]

That does sounds gear cooler-ish–Test at the dock— Put the two oil together (flare union or ?)  and  see if it goes away

[Lew]

Roger that Tony thx. I was thinking possibly gear oil cooler? the sheen appears to have a droplet like effect on the water that makes the sheen. I will report back. 

Thx

[Tony Athens]

There would be no connection between what you are experiencing.. Take the boat for a good run, touch WOT for a couple-three  seconds , maybe 2-3 times, to establish  a base line.. Make good notes: RPM. coolant temp, OP, exhaust color, etc) .. Then come back and post..        

[Author]

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