Film Floating on the Water

[denpooch]

Hey folks. Before I took her out for hibernation I noticed this film being produced by the exhaust on the port side. Starboard side is clean.
I know that it is not coolant, as I changed out the risers this season and she is holding the antifreeze. Also, she is not burning oil.
I am thinking that perhaps the engine is running rich, however I do not know if fuel injection systems can 'run rich'.
I have attached an image for reference. Any thoughts on cause and Spring cures are much appreciated. Gasoline engines are Crusader 6.0's.

Water Film .jpg

[bud37]

Just on cold start up ?, if so yes they do richen the mixture until the engine coolant warms up, maybe in need of a set of plugs...the other thing that gets missed is the PCV valve may need to be changed.
Hard to tell from the pic if that is an oil or gas sheen.

[mjk1040]

Got 2 agree with Bud, looks like a rich start up, wouldn't be concerned unless it continues next season a lot. Other than what Bud suggested, Check and clean spark arrestor 2!

[Viper]

Ya hard to tell what it is from a pic. Do you smell fuel when this happens, does it only happen until she comes up to temperature? There are a few things that will cause a rich mix. Aside from initial start up and dirty arrestor, a faulty sensor that tricks the ECM into thinking there is a condition requiring more fuel will result in a rich mix such as a failed temp sensor indicating the engine is cold when in fact it's warmed up. As long as the ECM reads a cold engine, it will deliver more fuel thus causing a rich condition. If it's fuel, it may also be due to a dead cylinder that isn't firing for one reason or another. Hopefully that is due simply to an ignition component failure, plug wire off, etc.

[denpooch]

Thanks everyone. I will monitor in the Spring and keep your suggestions in mind.