Surface rust in tank-big concern?

[Surly]

I drained the gas that had sat in my GS for the last 17 years. The tank was mostly full, and the gas had the pink tint that old gas has. Yeah, you can imagine the carbs after 17 years with that crap in them. There was no rust in the tank at that time.

I popped the cap off the tank last night and noticed a very fine patina of surface rust is starting to form. It wipes off easily, but should I be concerned about doing an acid treatment as I've been reading about, or just put some gas back in it and shake it up every couple of days to recoat the metal? I think the tank is sound, as it had gas in it while it was stored.

Hopefully, with the addition of one of Mr. Barr's o-ring kits I'll have this GS running by months end so long term storage procedeures aren't necessary.

As always, I appreciate the help.

[fgh]

That surface rust will wind up in your carbs if you let it form in the tank. THAT'S A VERY BAD THING. My advice is to get the rust out ASAP and refill the tank all the way with gas or add a cup of kerosene or diesel fuel and a cup of motor oil and shake it up about once a day. Once you're ready to start it you can drain that stuff and add at least 2 gallons of gas or so and go from there.

[Billy Ricks]

Check this thread, http://www.thegsresources.com/_forum...ad.php?t=93496 .

[Surly]

That's what I was afraid of. Okay, phos acid it is. Do I need to pull the petcock, etc. prior to doing this? What is a good neutralizing agent? Baking soda and water perhaps?

[HobieSun]

I used muriatic acid and it worked great. You can get this stuff at Menards for cheap $2, or anywhere usually where they sell pool stuff. You have to take everything off of the tank (petcock, fuel lever sender, etc) and what I did was used duct tape to close the bottom holes, put about a quart or so in it then taped the top and swished that stuff all around inside and let it sit for about 3-4 minutes. Then I took the tape off the top and ran a water hose down in it and let it run for about 30 minutes. Then I used a hair dryer to dry it out and it was a nice pretty silver inside when I was done. Hooked everything back together and now I still have an Electrical Problem!!! (didn't think it would fix that, but it did get the rust out of my tank)

[Billy Ricks]

Phosphoric acid is the safest. It won't hurt the sound metal and converts any rust that might be left behind to iron phosphate.

[Surly]

I am going to use the Behr Concrete Etcher and Rust Remover. It has Phos Acid in it, and the best part is that I still have some leftover from when I epoxyed my garage floor. Wow, I get my tank cleaned without spending more money and I get to get rid of a bottle I've been tripping over for the last two years? Does it get better? Sure, but I'll take a victory, however small it may be. I may even throw in some gravel just for kicks and more noise when I shake the tank to make me feel like I'm doing more than I really am.

Thanks guys.