sheen on the water

[nightsky]

I have Cummins 6BTA's on a 390. One engine is smoking more than the other and there appears to be fuel coming out of the exhaust port leaving a light sheen on the water. I was told it is likely unburned fuel due to one or more injectors with poor spray pattern resulting in incomplete burn. Does this sound right, or is there some other problem at play? There is more smoke coming from this engine. Cant tell if the smoke is more blue than black though.

Any comments or advice appreciated.

Joe
Pacific Horizons

[waybomb]

Pull the injectors and have them checked. I don't believe it's a difficult job.
Black smoke would be unburned fuel .

[Viper]

Source of the post Pull the injectors and have them checked. I don't believe it's a difficult job.
Black smoke would be unburned fuel .

+1

Also make sure air filters are clean so they're getting enough air for a complete burn.

Another possibility; are you sure the sheen is fuel and not engine or tranny oil from a failed cooler?

Is there a drop in performance?

[nightsky]

Source of the post Pull the injectors and have them checked. I don't believe it's a difficult job.
Black smoke would be unburned fuel .

Had a mechanic check the engines out before I bought the boat and he suggested it was injectors, so I will be pulling the injectors. I have already changed air filters but have not started engines up yet as we are still in drydock, so will check out that possibility on the trip to my home port.

[nightsky]

Source of the post

Source of the post Pull the injectors and have them checked. I don't believe it's a difficult job.
Black smoke would be unburned fuel .

+1

Also make sure air filters are clean so they're getting enough air for a complete burn.

Another possibility; are you sure the sheen is fuel and not engine or tranny oil from a failed cooler?

Is there a drop in performance?

I am not at all sure that the sheen could not be caused by oil cooler leak, will try to narrow the possibilities on the trip home after which I will pull injectors and also pull the oil cooler and aftercooler and heat exchanger and have them pressure tested. I will test the injectors first, based on the mechanics recommendation, then move on to the coolers if the problem persists.
thanks for comments and advice.

[Viper]

Ever find the problem?

[nightsky]

Thought the problem cleared itself up on the trip to home port. Re-started engine again yesterday after having been away for 2 weeks and problem has re-appeared. Will pull injectors now for servicing, and pull tranny oil cooler as well.