brown "peanut butter" at fuel tank out line

If you've been following this story, the airplane has had foreign substance(s) introduced into aircraft fuel tank.
I was meaning to clean out the fuel filter at the fuel tank and was confronted with this-brown "peanut butter" looking substance blocking about 20% of the tube leaving the fuel tank. I have only had automotive/no ethenal gasoline in it.

SECOND QUESTION: WHERE IS THE FUEL FILTER SUPPOSED TO BE? Is it stuck in the tin line forward of the opened joint shown in the picture?
THIRD QUESTION; HOW DO I GET TO THE COURSE FUEL FILTER?

My first response is you are looking at Proseal. I am making assumptions that this fitting is on the fuel tank since you did not specify. If that is true there is no filter inside the tank unless a builder (again assuming here, that is not you) did not deviate from the plans and place one inside the tank.

Assuming (doing a lot of that in this post) it is proseal, your options are:

• Clean it out as best you can.
• Locate your filter (follow the lines but many filters can be found on the floor underneath the center section cover on side by sides). Of course you did not state which airplane you have so it could be in many other places too.
• Open the filter up and clean it out if needed.
• Do a very thorough inspection around the tank looking for blue stains. If the proseal is breaking down you are very likely to find leaks.
• Finding leaks means repairs which will entail removal of the tank.

It might be helpful if you give more information on what airplane, fuel injection/carb, how old is the plane, etc. Some of this info can help with analysis of the problem.

My thoughts on where to start.

It is a vans RV 12. The fuel tank has two leads. I was not the builder.
Vans "Gus" told me that the fuel filter is somehow stuck in this line in this location. Looking up I see no filter.
I would have to somehow administer a pin into the down tube to see if there is a filter in there somewhere.
I expect that this is a common procedure so that is why I am asking as I assume many people have
1. located the fuel filter leaving the tank of an RV12
2. cleaned it,
3. replaced it.

That looks like Fuel Lube to me.

Of course it is a 12. My bad for not paying attention to which forum you posted. In my defense, I do not navigate to any forum. I simply look at ALL new posts in the TODAY'S POST section of the site.

I agree with ArveeNiner this could be fuel lube.

This question seems to have come full circle to one you asked a week or so ago in which you received a lot of tips regarding removing the line (with use a crows foot tool that I think you bought after that) and the finger screen at the bottom of the tank.

The blue fitting in your photo is the finger screen that has been described for you previously. It un-threads from the mounting flange on the tank

As has been mentioned many times previously, the RV-12 has a maintenance manual. Have you looked at that regarding cleaning fuel system filter screens?

Is it just me, or does the tube flair look a bit strange??

As has been mentioned many times previously, the RV-12 has a maintenance manual. Have you looked at that regarding cleaning fuel system filter screens?
Yes. I have searched and searched and looked at the maint. manual online and the hard copy I have here. It is sparce in its advise on where a course fuel filter is in this region. I am thinking of using wife's darning needle with hook to stick into tin gas line and see if it is down in there and I can fish it out (if it is there)
As I said elsewhere, I took apart the gascolator and found no filter there. Could the builder have done such a stupid thing as to not put fuel filters into the aircraft?

I am pretty sure the "filter" in the photo is actually a screen----called a "finger strainer" because it is about the size of your little finger. The screen is very coarse, keeps out big stuff only.



The gascolator has a screen also, it is in top portion of the unit, the part that is mounted to the firewall or whatever. The bowl does not have a filter, it is only to collect the crud that the screen keeps from flowing downstream.

Maint Manual table of contents shows fuel system is chapter 13

Page 13-3 has a diagram showing where the course and fine filters are located.

Page 13-7 gives details on cleaning and inspecting the gascolator and fine filter (inside the gascolator)

Page 13-8 gives details on removing/inspecting/cleaning the fuel strainer (Course filter)

As mentioned in my other post, the course filter/fuel strainer is the blue object in the photo in your first post of this thread.

See Page 149 in the MM.

Don't be hard on yourself. I built my plane and forgot about installing the strainer originally and the need to remove the strainer every year. Its thumb shaped and inside the tank. You are staring at the fitting in the picture you posted. You just need to unscrew it from the the tank to inspect. Ideally the MM would have a better picture, but its very very likely in there. You've evidently already completed steps 1-3 below. Fitting if I recall, can be removed with a deep socket and turning it counter clockwise.

------------------------------------

FUEL STRAINER REMOVAL
Tools 3/4 combo wrench or deep socket
Expendable Thread sealant paste
Replaceable None
Service Rating Line
Minimum Certification LSA-RM or A&P
Additional References KAI
NOTE: IT IS NOT NECESSARY TO REMOVE THE FUEL TANK IN ORDER TO REMOVE THE FUEL
STRAINER.
1. Drain the Fuel System. (13-4)
2. Remove the two aft access covers from the fuselage bottom skin. (3-4)
3. Disconnect the fuel line (forward most fitting) from the bottom of the tank.
4. Remove the fuel strainer.
5. Clean the screen and inspect same for breakage or separation from fitting.
Installation:
1. Installation procedure is reverse of the removal procedure. Apply thread sealant
paste to fuel strainer pipe threads before installation.

The RV-12 finger strainer is similar except it is integral with a blue AN flared fitting instead of the reducer fitting that is shown.

I don't see anything like the big insert fuel strainer here.
I was told by VANS ("Gus") and others that it is merely a course filter that "sits" either above or below that joint in the picture.
I see no fuel filter.
There was no fuel filter in the gascolator.
I wasn't the builder but have gotten many compliments from builders and a and p men that it was a "well built plane". But they didn't look where I've looked!

I have sued many for sabotage (hello Jonn) of the fuel and for breaking the link of the stabolator. So, if the builder didn't put filters in anywhere then I don't think that would have changed the outcome.

The piling up of the crud makes me suspect that the crud was stopped there by the course filter and not permitted to go foward in the fuel system. I just can't find the course fuel filter which I am told should be right there.


FUEL STRAINER REMOVAL
Tools 3/4 combo wrench or deep socket
Expendable Thread sealant paste
Replaceable None
Service Rating Line
Minimum Certification LSA-RM or A&P
Additional References KAI
NOTE: IT IS NOT NECESSARY TO REMOVE THE FUEL TANK IN ORDER TO REMOVE THE FUEL
STRAINER.
1. Drain the Fuel System. (13-4)
2. Remove the two aft access covers from the fuselage bottom skin. (3-4)
3. Disconnect the fuel line (forward most fitting) from the bottom of the tank.
4. Remove the fuel strainer.
5. Clean the screen and inspect same for breakage or separation from fitting.
Installation:
1. Installation procedure is reverse of the removal procedure. Apply thread sealant
paste to fuel strainer pipe threads before installation.
__________________

Have you removed the blue fitting from the bottom of the tank? You won't see the strainer (coarse "filter") until you do. It's attached, and inside the tank.

The fine "filter" is a very fine mesh screen inside the gascolator, as Scott mentioned and showed in his post.

There is no separate "fuel filter" as you might expect to see in an automotive installation. The strainer in the fuel tank is to catch large debris there, before it gets into your fuel lines and potentially causes a blockage. The fine screen in the gascolator is to catch smaller particles. Neither one will block everything. If you get a batch of bad gasoline (which can mainfest itself as a nasty brown sludge that smells like varnish) it can be squeezed through both and make its way to the carb where it can and will wreak havoc. Gasoline can and will go bad all by itself just sitting long enough. How long? It depends on temperature, humidity, ventilation, quality of the gas, and possibly planetary alignment or the frequency and sincerity of burnt offerings made to the aviation gods.

By the way, "Ron" who posts here put up some magnificent pages on his build of his RV 12 Here is his page on the fuel tank system http://rons-rv12.blogspot.com/p/fuel-tank.html

danielabernath said:

I have sued many for sabotage (hello Jonn) of the fuel and for breaking the link of the stabolator. So, if the builder didn't put filters in anywhere then I don't think that would have changed the outcome.

Click to expand...

What does this mean? Wait, not sure I really want to know!

Other than the course finger strainer that is screwed into the bottom of the fuel tank, and the fine screen inside of the gascolator, there is no other fuel filter. That is why you can not find it.
There is a very small filter inside of the engine driven fuel pump, but that is not accessible.

Mich48041 said:

Other than the course finger strainer that is screwed into the bottom of the fuel tank, and the fine screen inside of the gascolator, there is no other fuel filter. That is why you can not find it.
There is a very small filter inside of the engine driven fuel pump, but that is not accessible.

Click to expand...

I have a feeling Daniel never saw the fine mesh filter screen in the top of the gascolator because he has already posted that when he checked it there was no filter in it.

The gascolator doesn't have a filer element in the can like you might expect if you have only worked on trucks.

The filter is a screen in the top like shown in the photo that mike already posted.....

One more little tidbit--------this gascolator has a third fuel port that needs to be plugged. As I recall, there is one inlet, and two outlets. You choose outlet best fits for your mounting situation, than plug the other one. Some have a primer line port also, see thread below.

The inlet is the one that goes to the center of the bowl, if hooked up backwards, the screen can plug up rather quickly.

If by chance the lines are hooked up using both outlet ports, the fuel will pass straight through, and no filtering will take place.

Read this thread for more info. http://www.vansairforce.com/community/showthread.php?t=125673&highlight=gascolator

That "crud" you see looks like fuel lube to me. Is it soft and pasty or does it crumble apart ?

That "crud" you see looks like fuel lube to me. Is it soft and pasty or does it crumble apart ?From the picture it appears to be crumbly.