Aftermarket fuel/water separator drain mod

Aftermarket fuel/water separators lacks the drain hose on the bottom which can make a mess inside your unit when you do drain water. With two needle valves, a cap, some fuel line and clamps you can rig one together.

You'll need two 1/4in OD X 1/8in MIP angle needle valves and a 1/4in OD compression cap. I got these from Home depot in the plumbing department.

Remove the needle valve assembly from one of the pieces. The red arrow shows where the needle valve was screwed on, these threads will fit the fuel/water separator. I used a bit of yellow Teflon tape to be sure to seal everything up.

The plastic screw that comes with the fuel/water separator has a small o-ring on it which I also used. It goes on the threads that will screw into the fuel/water separator.


The cap is used to close off the extra opening. It is shown here with the red arrow.

From there just use a length of fuel line and some hose clamps to make a drain. I made mine about 18 inches, long enough to get it out the door for when I want to drain the fuel/water separator.

I believe the issue that everyone was having was no one could find a fitting with the proper thread pattern that would fit the bottom of the fuel/water separator. I just so happened to get lucky and randomly tried the threads from where the needle valve is screwed onto which happened to work.

If anyone has any questions or has problems sourcing these parts let me know and I'll try to help.

Thanks

I did some measuring of the plug on one of the Napa 3472 filters and it came out to 3/8-28, straight threads (not tapered). That is 1/8-BSPP. The drain petcock I removed from the original filter is 1/8 NPT. So I ordered a 1/8-BSPP male to 1/8 NPT female adapter and hooked up the original drain valve to the Napa filter. It was a little tight on the OD like my particular adapter might have been on the large end of tolerance but it screwed into the filter with just a little force. I tested 2 filters and both fit the same way, and the original plug still fit fine in both afterwards so the tight fit doesn't appear to be problematic.

If you want the remote drain hose without the hose itself being pressurized when the set is running, here's a way to do it with the Napa filters.