In the absence of any flow direction arrow, does it matter which way an inline fuel filter is fitted - ie should any debris be captured on the inside or outside of the actual filter?

Thanks.

I buy mine by the dozen from a power & equipment shop just down the road from me and I asked them that exact question because theirs had no flow arrows. I was told that the type of filters with no flow arrows can be installed either way. The filter media is different than the ones with flow arrows. I assume it uses a 75-150 micron screen, or something similar. They are white plastic and you cannot see the insides.

I also have a few that are clear plastic using a paper element and they do have flow arrows. But they are bigger than the white plastic filters and are sometimes hard to fit in the short length of fuel line.

Thanks Schu.

As it happens, I've just been to my local shop to buy some new ones. At first glance, they are identical to the one I've just broken  , but they now have a directional arrow - if you look hard, you can see it in the last photo in the attached link. So it seems, to answer my own question, that the filtering takes place on the outside of the mesh.

Carburation/Fuel :: Air & Fuel Filters :: Fuel Filters :: 8mm Inline Fuel Filter - Clear Polycarbonate with Micro Mesh - 21mm Diameter

Outside