Black stuff in gas tank

[Brentwood Bob]

Several of us have flushed, and filtered gas from gas tanks to remove a black flacky stuff out that is clooging up the fuel line. I used coffee filter and plumbed a 1/4 inch line from the outlet(31 indented firewall) out over the fender to a large funnel and a 5 gal gas can.There was a shutoff valve right out of the tank. then I put a short nipple and an elbow.
Any body know what we are fighting? What is that black stuff?

[Dennis Pereira]

B P gas sorry

[Ron in Quincy]

Hopefully its not old tank sealer that was available in the early 80's; it was not impervious to the additives in the gasoline and would, over a period of time, start desolving the liner.

Ron

[sunnyorm]

i have a similar problem, i have gotten to it yet, but my model a mentor suggested i flush with water, to see if it breaks down

[Richard in Anaheim CA]

I had the same problem from gas left in the tank for 9 years. It looked like permatex.

A friend suggested since it was gas, maybe gas would desolve it. Intreresting theory. I drained what was left in the tank and put fresh gas in and rocked the car every time I thought about it for several days.

It did start the process, albet slowly.

I drained it and dumped in two gallons of carbuerator cleaner, heated it with a shop quartz light over night and then flushed with water using a strong garden nozzle. It worked. Even the gas float disappeared.

My final sequence was Por 15 Marine Clean diluted 50% and heated with a shop quartz light overnight. It got about the temperature of hot coffee.
I rocked it around, drained it, flushed with afore mentioned nozzle and it was clean enough to eat out of. Replaced float with wine bottle cork.

I wasn't about to remove the tank and the paint.

Richard
Anaheim CA

[Brentwood Bob]

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Could be an old tank coating. Each tank had sat at least one year before recent attempts to get the cars roadworthy. We stayed with the filtering and reflushing technique, but we only put thru 5 gallons at a time. We do feel that the pipe gives us a better flow out, Some of the black stuff is like round balls. Bob

[Ron in Quincy]

Ascetone will cut the old tank sealer. A friend of mine, who was concerned as his tank had been sealed, purchased 3 gallons of ascetone, put it in the tank; we rocked the A back and forth for about 10 minutes then drained the tank ; put a couple of gallons of gas in and did the process. When we were finished the tank was clean, he didn't have to repaint, and never had a problem in the future.

Ron

[Brentwood Bob]

Acetone. One car has a nice paint job, but it has the worst problem. Thanks. We thought of lacquer thinner. I'm leaning toward the Marine clean. Thanks for the ideas. Bob

[Keith True]

It does sound like a tank sealer,but to have several cars doing the same thing is kind of odd.That is,unless a bunch of buddies all did the same thing.Many years ago a garage here would mix up Permatex and alcohol,and swish it around the tank.The gas would not bother it,at least not for the last 35-40 years.Now they are all coming apart.It kind of looks like thin flakes of black oatmeal.For the most part it is being caught by the sediment bowls,I am seeing it on old tractors and most have the glass bowls.(except Fords) The guy that did it warned everybody not to use Cumberland Farms gas,they started selling Gasahol here in 1980.

[Brentwood Bob]

What I filtered out was thin black flakes. The other car has a different type forming small balls in part of it. We both think we will see this problem again, and we are working thru it. Pulling a painted tank to clean, or replace with another would be difficult. I hope that on future projects I always make sure I know the interior condition of the tank first. I think I'll put a small hand held mirror in my road repair bag, this guy has a real hard time seeing the inside of the tank over the fenders.

[Ken Ehrenhofer]

The biggest component in Lacquer thinner is MEK. Methyl Ethyl Ketone is in the same family of solvents as Acetone. Be very careful when using as they are both very flammable. both will remove lacquer paint upon contact so make sure you do not spill on the paint surface. Do not create sparks when working with it. We use to use brass scrapers and hammers in the painting industry so we could not create a spark.
Just some thoughts about safety when we talk about MEK or acetone,
By the way acetone is in finger nail polish remover,
Ken

[Brentwood Bob]

On removal of the intake and exhaust a permatex like buildup is in the intake, and the interior of the carb throat. Lacquer thinner cut it with a 1 hour soak, and some scrubbing. Looks like this will be a fun project.