What fuel filter to use for a carburated engine?

ArVeeNiner · #1 02-27-2009, 04:29 PM

Hi all:

So, I've read the thousands

of posts regarding the placement of the fuel flow transducer supplied in the Dynon kit. I came up with before the mechanical pump...no after...no, on the engine...no, in line....ARRGHHH! Then I read a bit about placement of a fuel filter and I came up with after the electric fuel pump....no, before....no, at each tanks output. My head started to hurt!

So, I'm going to start with the basics. If I elect to mess with the fuel lines in the cockpit which have been in place for a very long time (read here that I'd rather not mess with them), what fuel filter do I use upstream of the electric pump? If I decide to put it on the engine side of the firewall, which do I use? I've see on Aircraft Spruce simple $4 inline glass filters much like I have in my VW Thing. I also know there are $200 filters too. With all our nice fuel lines running both in the cockpit and in the engine compartment, do we really want to revert to a simple glass filter with a clamp and a rubber hose at each end? How would you plumb that anyway?

I have a very basic set up. I have the Van's electric fuel pump and a carburator...that's it.

Kyle Boatright · #2 02-27-2009, 04:39 PM

Quote:

Originally Posted by ArVeeNiner

Hi all:

So, I've read the thousands

of posts regarding the placement of the fuel flow transducer supplied in the Dynon kit. I came up with before the mechanical pump...no after...no, on the engine...no, in line....ARRGHHH! Then I read a bit about placement of a fuel filter and I came up with after the electric fuel pump....no, before....no, at each tanks output. My head started to hurt!

So, I'm going to start with the basics. If I elect to mess with the fuel lines in the cockpit which have been in place for a very long time (read here that I'd rather not mess with them), what fuel filter do I use upstream of the electric pump? If I decide to put it on the engine side of the firewall, which do I use? I've see on Aircraft Spruce simple $4 inline glass filters much like I have in my VW Thing. I also know there are $200 filters too. With all our nice fuel lines running both in the cockpit and in the engine compartment, do we really want to revert to a simple glass filter with a clamp and a rubber hose at each end? How would you plumb that anyway?

I have a very basic set up. I have the Van's electric fuel pump and a carburator...that's it.

First, a question: Do you plan on having a gascolator? If so, it serves as a crude filter.

Second, an opinion: If I planned on using filters, I'd put 'em in the wing roots. Eventually they will need to be changed and if they are in the cockpit, fuel is going to end up being spilled on the carpet, upholstry, etc. Also if (when?) the filters leak, the leaks won't be inside the passenger compartment.

N941WR · #3 02-27-2009, 04:41 PM

I suggest you build per the plans. There are thousands of RV's flying with a gascolator.

In my case the Dynon fuel flow is after the gascolator and works fine. Check my web site for pictures.

ArVeeNiner · #4 02-27-2009, 04:54 PM

Quote:

Originally Posted by N941WR

I suggest you build per the plans. There are thousands of RV's flying with a gascolator.

In my case the Dynon fuel flow is after the gascolator and works fine. Check my web site for pictures.

Yes, I have the gascolator supplied by Van's. So, that can take the place of a fuel filter?

N941WR · #5 02-27-2009, 04:58 PM

Quote:

Originally Posted by ArVeeNiner

Yes, I have the gascolator supplied by Van's. So, that can take the place of a fuel filter?

That IS the filter.

Walt · #6 02-27-2009, 05:36 PM

I've always used a filter after the selector, this protects the electric fuel pump from debris/clogging. The flow Ezy 3ILA works perfect and is available in your choice of elements, I use the 74micron size.

ArVeeNiner · #7 02-27-2009, 07:38 PM

Quote:

Originally Posted by N941WR

That IS the filter.

You know, that's what I thought but I started reading about all these other posts concerning filters and such and I started wondering. So is all this filter talk only a concern if you have FI? I think there is some sort of super electric pump that some people put in near the fuel valve that has a filter near it. Maybe you don't need a gascolator for this set up?

The bottom line is, since the gascolator is the filter, it looks like I'm good to go w/o adding an additional filter, unless I want to put one upstream from the electric fuel pump.

Thanks!!!

N941WR · #8 02-27-2009, 08:11 PM

Quote:

Originally Posted by ArVeeNiner

... So is all this filter talk only a concern if you have FI? I think there is some sort of super electric pump that some people put in near the fuel valve that has a filter near it. Maybe you don't need a gascolator for this set up?
...
Thanks!!!

IO engines use a high pressure fuel pump and drop the gascolator, thus their need for an inline filter. Also, the UK requires filters on each tank, thus some mount gascolators or filters in each wing root.

Most certified planes run with one simple gascolator, if they have a carb. They have been using them for years and they seem to work fine. BTW, gascolators also work as a water trap, which most filters do not.

Special Delivery · #9 02-27-2009, 08:28 PM

There are many ways to skin a cat... here's what I use on each tank BEFORE the selector valve > here

MrNomad · #10 02-28-2009, 02:52 AM

There is also a fuel filter inside the carb of my O-360. It's about 3" long, about 3/8" wide, looks like a brass screen that's been rolled, and it receives fuel from the fuel line. It's easily ruined if you do not allow it to center as you attach the fuel line to the carb.

Ask me how I know.