Cleaning gas tank

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Steve Webb
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Cleaning gas tank

Post by Steve Webb » Sun Nov 25, 2018 6:51 am

Is there anything I can do to help clean older residue from a tank still in the jeep. I left it sitting for a long time and did drain it some months ago and put rags in to soak up what did not come out. I do not want to continue getting jeep going and have problems with fuel pump/carb sending crap into them. I had it cleaned and sealed many years ago so not worried about rust but the varnish smell is very strong. I have 1 gallon of fresh gas in there now but anything I can try to keep from removing the tank would be helpful. 3a jeep. Also while I am at it fuel line from tank to pump inside the steel line. Thanks
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Re: Cleaning gas tank

Post by Wolfman » Sun Nov 25, 2018 9:03 am

Pretty much depends on the condition of the tank bottom. If the only problem is the smell, should not cause any problem. It will dissipate.
If there is a layer of dried varnish on the bottom, anything that will break it loose is going to cause you problems. You can only get to a small part of the tank with a rag on a stick. The rest is going to float around and end up in the fuel line.
Take the fuel cap off and look in with a flashlight. Use a wooden stick to scrape the bottom and see if anything comes loose.
Off the top off my head, I don't remember how the pick up is made in a CJ tank. Like a military pick up, with a tube & screen or just an outlet fitting with no pick up tube. If it is just an outlet fitting, you might be able to remove the fitting and run fresh gas through the tank and let it drain out the fitting hole, in the bottom, into a pan. But that will be marginal. If it is too bad, out with the tank.
I have a couple of CJ tanks in the shop. I will check them out, as to the outlet, and get back with you. May be tomorrow.
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Re: Cleaning gas tank

Post by Ben Dover » Sun Nov 25, 2018 10:34 am

Acetone is a recommended remedy for cleaning a Jeep fuel tank. Dump in a quart to clean out residue.
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Wolfman
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Re: Cleaning gas tank

Post by Wolfman » Sun Nov 25, 2018 12:51 pm

OK, Steve. First round Sunday football, so far, has me bored, so I went out to the shop.
I have 3 CJ tanks. 2 OEM and 1 Re-Pop.
All three have fuel outlet fittings where the fuel line connects and a small drain sump with a plug, in the same location on each. Right rear as you are sitting in the seat with the tank installed.
The OEM tanks have a steel line inside that connects to the outlet fitting, the steel inner line loops up and back down in the vicinity of the drain sump with the drain plug. Pick up point is pretty close to the bottom of the tank. The Re-Pop tank does not have the looped line inside. Just pulls the fuel from the bottom of the tank, like some old farm tractors. There is a baffle that runs left to right, tank center, the width of the tank, in all 3 tanks but the baffle does not touch the bottom of the tank. There is about a 1/4 inch gap between the baffle bottom and tank bottom.
So. If the tank is not fouled too bad, you could put fresh gas. Acetone. Lacquer thinner. Something that will cut varnish in the tank. Let it soak a bit. Maybe stir it with a wood stick, best you can, then drain the mix out the drain sump plug. Then flush it again with fresh gas a couple of times.
If you are still concerned about particles getting to the fuel pump and/or carb, you could install an in-line filter in the fuel line between the tank and fuel pump. In the rubber line between the frame and fuel pump would be a good location. Have one there on my CJ.
Then again, if after inspection, the tank bottom looks OK and caused no problem in the past, you would be good to go as is. The smell will eventually go away.
Hope this helps ! Go Colts !
Mike Wolford
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Steve Webb
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Re: Cleaning gas tank

Post by Steve Webb » Sun Nov 25, 2018 1:00 pm

I will get in and look closer. I had put a fuel filter after pump and before carb but will see about maybe moving it. I rebuilt and installed my original fuel pump and started to get jeep going but thought maybe I am creating a new set of problems. 3rd year of not watching NFL so Sunday's are easy. Helps being a Dolphin fan since they suck so you get used to no pro football :D
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Re: Cleaning gas tank

Post by Steve Webb » Sun Nov 25, 2018 5:46 pm

Found a little over 1/2 qt of acetone so it is in tank. I'll drain it sometime this week and take a peek of inside and check to see if anything is loose on bottom.
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Re: Cleaning gas tank

Post by Wolfman » Mon Nov 26, 2018 8:13 am

Not sure how far a pint of Acetone will go ??
Guess we will find out.
Let us know.
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Re: Cleaning gas tank

Post by W. Winget » Mon Nov 26, 2018 10:06 am

Too late now, but depending on what your tank "was" lined with, the acetone may have just compounded the problem by eating it away.

I would have recommended lye (crystal Drain cleaner) and hot water, but you stated it was lined, so I backed off on the recommendation.

Good luck with it, not all recommendations are correct, hope the lining isn't ruined.
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Re: Cleaning gas tank

Post by Chuck W. » Tue Nov 27, 2018 3:52 pm

I had it cleaned and sealed many years ago
Too late now, but depending on what your tank "was" lined with, the acetone may have just compounded the problem by eating it away.
I was going to say the same thing! If you used Red-Kote, you may be OK, but coatings like POR-15 don't like acetone. I'd recommend you dump it immediately and just use hot water.
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Steve Webb
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Re: Cleaning gas tank

Post by Steve Webb » Tue Nov 27, 2018 7:24 pm

I did not do the tank cleaning/ coating. It was done by a business that cleaned repaired radiators for many years probably best known in the county. Full auto service and an entire building just for work like this. Gave it a look inside yesterday and nothing loose or floating so may not have an issue. If nothing else a good for someone doing a search down the road
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