fuel sheen coming from exhaust

[Magnarae]

I noticed a heavy sheen coming from my exhaust when I started the boat to haul it for the winter. I have always noticed a slight sheen, but nothing like this past time. The boat has a 2002 315 Yanmar with approx. 650 hours. The valve seals and timing belt where changed two years ago. The engine runs like a top. I thought it might be a fuel injector, but wouldn't the boat run rough? This is my first diesel. Any suggestions as to what may be causing this? I attached a link to a video I uploaded to YouTube

https://youtu.be/El188eBwsFE

[Russell]

This might just be normal until the engine warms up. It indicates unburnt fuel and if it persists after the engine is warm it may also be due to a dirty air filter.

[Magnarae]

Russ it definitely dissipates when she warms up. I always see a little bit, but this just looked to be more than I was used to seeing.