I've done lots of googling and think I may have a lead on the brown liquid. It may be the result of surfactants.
The term "surfactants" is a contraction of "Surface Active Agents." These
soap or detergent-like materials occur naturally in fuel. They may also
be introduced in the refining processes by the inclusion of additives into
the fuel, or they may be washed off the internal surfaces of containers
previously holding other products. Surfactants are usually more soluble
in water than in fuel and reduce the interfacial tension between water and
fuel; this stabilizes suspended water droplets and contaminants in the
fuel. Surfactants adhere to filters/separators and reduce their
effectiveness. They also adhere to metal surfaces until surfactant-rich
water droplets are formed. The droplets run down the sides of fuel tanks
and form puddles in the bottom or in the sumps. Surfactants in large
concentrations usually appear as a tan to dark brown liquid with a
sudsy-like water/fuel interface.
Now I confess I have added "SeaFoam" to the fuel when the engine was running rough and it immediately improved engine performance but longer term it may also be the cause of the "brown liquid"
So that's my best guess. I've still got about 25 gallons of "SeaFoam enhanced" fuel on board. I'll continue to take samples from the Raycor. I suspect I'll still need to polish the fuel with something like the "Austin Fuel Polisher" :lol:
This morning, with the new filter, the Honda was purring like new and there is no residual brown liquid in the filter :thup
Phil