View Full Version : Fuel / Water Separator

10-03-2004, 11:42 PM
After searching hi and low locally for a replacement fuel / water separator for my boat I finally realized that I'd have to order one from DIM. But in my searching I found some pictures of my FRAM separator and it shows the filter cartridge mounted upside down from how the local dealer installed it... And it looking at this thing I'm baffled as to how it works. Can anyone help me out with how it works and which way the cartridge should go?

I do know that water is heavier than gas and that I can drain the collected water by opening the little drain at the bottom of the canister. But why doesn't gas come out too? Also, when I took off the canister (to figure out which filter it was) the fuel was almost up to the top. But after I drained the fuel I noticed that the bottom half of the canister looked a little corroded, like it had water in it as some point in it's life, but the top half was shiny as ever. Does the fuel only go so far down? :confused: Also when I put it back on, I'm assuming that I should fill it back up a bit (so I'm not sucking a ton of air into the fuel pump) Do I put fuel in the outside or the inside of the filter? Or maybe fill the canister up partway and then push the filter on.... ????

10-04-2004, 01:29 AM

My only experience with water separating fuel filters was on industrial equipment many years ago..

I can't tell you exactly how they work, but I do know that the material they use in them is designed to separate water out from the gas. I believe the top part is to do 2 jobs: 1) filter the gas; and 2) take the minute particles of moisture and turn them into larger droplets, the bottom part separates out the droplets so they can fall to the bottom of the canister.

I do know that you're not supposed to touch the 'paper' with your fingers - the oil from your skin can wreck the effectiveness of the separator..

I would follow the Fram picture. It's possible the dealer put it in wrong.

I would not re-fill the filter with gas. If your float bowl is full, there should be enough in it to run your engine long enough for the fuel pump to do its job.