Sheen

[KEVMAR]

During our sea trial and survey yesterday on a 1987 43 ft president I noticed a sheen on the water on the back of the boat what could be some of the causes of this should I get an engine survey I don’t know how long it had been run before yesterday

 

[DavidM]

I suspect you have Lehman or Perkins engines. These often produce a sheen which is unburned fuel. It usually diminishes after the engines warm up. Totally normal.


But that does not eliminate the need for an engine survey.


David

 

[STB]

What type of engines?

Was the sheen by one engine's exhaust? Both exhausts? Generator exhaust? Some other thru-hull? Surrounding the whole boat? Just this boat? Or other boats?

Was the sheen only at idle at the slip, or did it follow the boat?

Was it still doing it at the slip upon return?

Was the boat smoking initially at the slip? At cruise? Heavy to WOT? Upon return at the slip? If so, how much and what color?

If you put a diaper or paper towel into the sheen to soak it up, how does the towel or diaper smell? Diesel? Burnt oil? Nothing?

My last boat's Perkins 6.354MGTs loved to white smoke and sheen at start-up and until warmed up. Every mechanic called it normal. Perkins dealer came out and told me even rebuilding wouldn't fix it on that model. I spent a lot of $$ trying to fix what wasn't broke before believing them. So, as David wrote, very normal on many old school Diesels.

 

[KEVMAR]

1987 Lehman 275 turbo yes sheen on start up and return looked like both engines ,did not see it following White smoke on start up did not see when under way .

 

[STB]

Unless crazy excessive, I'd consider some white or light grey smoke and some fuel sheen at startup normal for those engines. Clearing up underway is a normal and good thing, of course.

I'm a little surprised there was significant smoke, and especially a sheen upon return. But, I have very little experience with the turbo versions of that motor.

I'll bet those who have them, or know them better than me, will tell you that isn't uncommon. But, I dont know that. I'm sure they'll chime in!

If old-school diesel engines otherwise run well, a little exessive white smoke or sheen at the slip usually pointa to injectors, injector pump timing, or fuel filters more often than a deeply rooted or super expensive issue.

 

[syjos]

My 120 Lehman 6,000 hours always leaves a sheen.

I think an injection pump rebuild woul mitigate the sheen from unburned fuel.

 

[waddenkruiser]

2x FL120, 4000 hours. Sheen sometimes direct after start, disappears within a minute. Seldom when shut down, especially after longer operation at low rpm.
Was the same with our previous FL.