As to what this is?  I'm assuming some sort of filter.  Whatever it is it appears to be leaking and I want to replace it.  It's on the fuel fill line.

It's either a filter or a check-valve (only allows liquid to go one direction, prevents 'splash-back')

Looks like a generic fuel filter for a small engine. The CE mark means it can be legally sold in the countries of the European Union. And they must be installed in the correct direction.

 

They come in different micron ratings, so check your manual or use West Marine's part finder or something similar. I have them on a John Deere riding mower and a Toro ztr. The motor makers - Kawasaki and Kohler - spec certain flow rates and right now I can't tell you how many microns they are.

 

Here's the blurb for one filter at West Marine. 

 

www.westmarine.com/buy/sierra--18-7712-inline-fuel-filter--10505089?gclid=EAIaIQobChMI3OnVk7r4-AIVNv_jBx1_YAIiEAkYCCABEgJPn_D_BwE

 

"Compatible with many 1999 and newer 4hp and 5 hp 2-cycle outboards and 1999 or new 4hp, 5hp and 6hp 4-stroke outboards

• Compatible with many 2005 and new 8hp and 9.9hp 4-stroke outboards and 2008 and newer 15hp and 20hp 4-stroke outboards

See our Engine Parts Selector to confirm this filter is right (or to find the correct one)"