Fuel filter funnels

[briblack]

Do the ubiquitous fuel filter funnels so many of us use really work to separate water? How well? And do they eventually lose their effectiveness? I think there's a coating on the screen, maybe teflon?

[sailorboy1]

I have one and use it when moving gas between my big and small can.

Once I just took some seawater and poured it in the funnel to see what would happen. ............................................. It just went right through!

So I think they are good filters for dirt, but pretty questionable for water.

[Pete17C]

correct on the teflon

not sure about it wearing out, or how effective the filters are

"The Racor Filter Funnel comes complete with a built-in DuPont Teflon® PTFE (polytetrafluoroethylene) coated stainless steel screen filter. As fuel is being filtered, free water and contaminates collect on the bottom. Because water is heavier than fuel, free water will settle to the bottom. When you have a substantial amount of water (approximately 1 cup), dispose of it properly and resume refueling."

[billknny]

Originally Posted by briblack

Do the ubiquitous fuel filter funnels so many of us use really work to separate water? How well? And do they eventually lose their effectiveness? I think there's a coating on the screen, maybe teflon?

Yes, they have a hydrophobic coating on the screen. They work very well at removing small amounts of water. The key is making sure that the water level in the "sump" of the funnel does not rise up to the bottom of the screen. If it does, it will pass the screen.

If you pour water into them, it will flow through. If the screen stays submerged in fuel, the water can't go through it beads up and falls down.

This type is much better at removing water than the traditional "Baja" type filter. However, it has a much lower capacity for catching and holding solid dirt. But... if the fuel has SO much dirt it overwhelms the screen... maybe you shouldn't be putting it in your tank!!!

I would not consider these filters as a way of purifying bad fuel, but rather as a tool for identifying dirty and/or wet fuel before too much of it goes into my tank.

[kapnd]

I put my money into an oversized fuel filtration system after spilling diesel into the water more times than I like to admit!
The funnels are clumsy, and block the sight and sound signals that let you know the tank is almost full, and I’m not at all sure that they adequately stop water.
I now have a Double Double Fleetguard filtration system from Seaboard Marine that easily handles any water or crud that the tanks may accumulate or perhaps already have.
It gives me triple graduated filtration and the option of switching to a fresh set of filters should the need arise.
All filters have bottom drains, super easy to operate, and they do often give me some water after a long run.
I think that most all diesel fuel does contain at least some water, and now I am confident that it cannot get past the filters!

[briblack]

I've got dual Racors on our boats engine, but I also like to check the outboard fuel, and keep it as clean and dry as possible. I use the filter funnel for that, too, and also have added a water separating filter in its fuel line.