hopefully the answers will be an easy fix.. i have a steel tank that i want to use on my latest project. It has been in the garage for YEARS the fuel was all gummed up and the tank had some surface rust. On the inside it has surface rust i'e bathed and swilled it out with petroil several times and got tonnes of rust out i've flushed it out with a high pressure water jet and filled it with pebbles and shaken vigoursly and washed and flushed etc etc about 2 hours in all. its improving but theres still a away to go though the bits that have cleaned up are now bright and shiny.. anything else i can do or am i bought into repeating the above evry night for the winter?

borrow a cement mixer, add to tank some sharp pea shingle or old nuts and bolts and wrap the tank in a duvet/bubble wrap and duct tape put it in the mixer start up and go for a cupa or two should take about an hour or so to completely clean the inside

See if you can get Phosporic Acid at your hardware/paint store. It is the key ingredient in most rust removers and will do a good job of cleaning the rust without damaging the good metal. Do not use Muriatic acid - it causes the metal to become brittle. Plug the drain and put the phosporic acid in the tank and allow it to work until the rust is gone. When finished dump out the used acid and dilute it with water. Then quickly rinse the tank out with warm water, then follow the water with a rinse of Acetone that will dry out the remove water - keep rising with Acetone until it comes out clear - the presence of absorbed water in acetone will make it cloudy.

Now.....you will probably want to coat the tank to prevent it from rusting again. The new ethanol fuels will quickly rust an unprotected steel tank. I like the POR15 tank lining as it is dark silver colored and it cures by contact with moisture in the air and is very durable. Most of the other tanks liners are white and acetone based.......and I have read of people that have had trouble with some of them with the new fuels.

thanks for the replies.. what new fuels?

When I typed "New Fuels" I was referring to the ethanol blends that are taking over the US. In an effort to reduce pollution and clean up the envorinment the Environmental Protection Agency has made it so that it is almost impossible to get anything that is not blended with 10% ethanol. While this works fine for new cars with fuel injection, plastic fuel tanks and modern plumbing - it can be a real problems for older equipment and it may be that the EPA is hoping that all the older equipment will go away. (This is pretty typical of the government employee turning a blind eye to the needs of farmers and small businesses). Rubber parts dissolve, aluminum parts corrode and steel fuel tanks rust as a result of the ethanol. The ethanol will gradually absorb moisture from the air and then the fuel starts to corrode aluminum and rust steel parts. It only takes a couple of months for the fuel to break down. Equipment that is only used periodically becomes impossible to start when it is needed again, and it has become necessary to drain the fuel out of any equipment that will not be used for a few months. Fuel stabilizers help - but the only sure way to prevent the damage is to drain the fuel out of the equipment until it is needed again.

The ethanol fuel caused the fuel tank on my brand new Sherco to become soft and swell in only 4 months. I now only use fuel that I get from the distributor that has not been blended with ethanol.

Here's a very good article from 2008 on the Jawa/CZ owners club web site. Clink this link.

The article quotes from the 'Federation of British Historic Vehicles Clubs' newsletters and a CONCAWE report - (CONCAWE is 'The Oil Companies European association for health, safety and environment in refining and distribution').

I've lined fibre glass tanks with 'Flowliner' epoxy resin but it peeled off due to the lack of adhesion. Wyldes do say that it is not designed for GRP so I guess I had it coming! I've also used it on steel tanks where it can stick to the rust and it seems fine so far.

If ethanol affects steel and aluminium, where do we go next?

Caswell seem to have the answer with their 'Gas Tank Sealer' - unless of course someone out there knows better! Caswell link

In case anyone out there still has any doubts, 'Old Bike Mart' has an article titled 'Are modern fuels bad for older engines?' on pages 18/19.

The good news is that there seems to be one or two more ethanol resistant products coming onto the market for example Sureseal from Tank Care Products in Norwich.

If you don't seal it then only way it to prevent problems is to empty fibre glass tanks after every event and steel and alloy tanks when they are not used for long periods eg over winter.

Things are only going to get worse with fuel lines, o rings, plastic floats all beginning to suffer.

And that's with only 5% ethanol (E5). Beware of E10 and E15 to follow.

Heard about 'Phase separation'? No, nor had I; and that's the fuel it refers to!

Be aware - believe!