After dealing with rough idle issues on my Edelbrock 1404, manual choke, 500 cfm carburetor installed on my 292 (bored to 301), I decided to pull it to see what was going on. Before I did so, I pulled a spark plug - yep, fuel-fouled.

Since I could not get the idle mixture screws to respond, nor the idle set screw to cooperate, I hooked up a vacuum gauge - it showed 19-20 and vibration between the two measurements. Of course, with idle rough this was an easy assessment. I also could not get any signal from the timed advance port on the carburetor. Off the carburetor came, and I am glad I did!
 
What resembles rust in the photo above was actually a very smooth film of wet good. Very odd stuff. Check out these butterflies:

Not quite sure what all of that was about since my air filter is basically new, the cleaner seals well, and I do not leave the carb without the cleaner installed. The real kicker were the fuel bowls. In addition to sediment, there were some "floaties" in there, and also some material stuck to the inlet screens.

After breaking out the magnifying glass, it became readily apparent that the material was indeed paper product from the fuel filter element. I disassembled both filters that I had on the car that had paper elements: the canister at the fuel pump and the inline filter. The fuel pump was fine, but the inline was falling apart at the edge nears the outlet of the filter housing. Yuck.

An ultrasonic cleaner worked well with Awesome cleaner, Vinegar, and water. What a difference.


A couple odd things: I did not see much in the way of ethanol deposits. As I recall, I did run at least one tank with ethanol, but the other tanks of fuel I did use Eastwood's ethanol treatment. Seems like that made a difference. Also, the passenger side metering rod was literally stuck in the jet with this rusty looking goo when I disassembled the top plate. The spring did not pop-it-up like normal.

Does anyone know what causes that rusty looking film?

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

https://vimeo.com/331281127

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

Video wasn't working for me.
Does the car sit for long periods of time? If so maybe you are experiencing phase separation of the fuel. Just a shot in the dark...

Thanks Dan for sharing this story with everyone. Looks like one more device to be added to the destruction list caused by our fuel.  This clearly shows the original style filter in the can under the fuel pump is the best and most effective design.  I'm amazed at how  sooooo much of this paper junk can make it's way out of the fuel bowl and land on top of things within the air horn? Maybe because the needle valve is not seating completely, causing a high fuel level would allow fuel to percolate out of the bowl vents???


64F100 57FAIRLANE500

There should be no vacuum out of the timed (or ported) vacuum port at idle so that is normal.


Lawrenceville, GA

Wow. I've never trusted the inline plastic filters. I use a glass bowled AC between the fuel pump and carbs. This is am eye opener for sure... thanks for the posting

56 Vic, B'Ville 200 MPH Club Member, So Cal.

I think I would change fuel stations after looking at that condensation rust from either the tanker trucks, fuel tanks, or your fuel tank.  The fuel with ethanol tends to draw moisture from the air and it will rust anything that is not plated or corrosive resistant like a gas tank, or old steel fuel lines to the carburetor.  On my Thunderbird, the fuel will literally evaporate within a few days and coat the pump nozzles with crud that has to be physically cleaned off before the engine will start and run at idle.  It all goes back to the blended fuels we are forced to use in these older vehicles that is designed for closed systems and high fuel pressures.  Joe-JDC

JDC

I have changed all of my spark plugs.
The carburetor is back on the engine, waiting to be plumbed.
I will install a metal screen type inline filter - no more paper element job.
I will keep the Fuel Pump canister filter as is.
I will look for a gas station that sells ethanol-free fuel.

I will cross my fingers. 

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

Thanks Charlie, I did wonder about that.

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

had 2 napa fuel filters(see threw) wherbthe glue failed and it entered the carb(.Made in china) luckily i could see the element moving away wher it was glued,ther answer was buy the metal 1. so you can't see the shit happening so i went elsewhere