Problems With Old Gas Left In Tanks

[av8rbc]

A question for the group - I came across a Kitfox where the gas had been left in the tanks for around 13 months. Owner says there is a "film" inside the tank.

Some of my flying buddies says the film adheres so hard that it will not flake off causing blockages. Rotax tells me to flush tanks and lines with new gas and carb clean spray the carburetors. Should be no problem. ?? Hmmm. :confused:

Your thoughts.

Gary

[n85ae]

Why not fill the tanks, let it sit for a week or so, drain the tanks through a
cheesecloth, or fine screen, and see what comes out. Maybe do a couple
iterations of this and see if crud is coming out? If after a few weeks of fill,
sit, drain, if nothing comes out you're probably in good shape.

Make sure to let it sit a week or so between straining, so it gets a good
long time to soften the crud (if it's gonna soften, since it might not). A
month or two of this, is a lot less hassle than replacing the tanks.

You do have finger strainers, and good filter as well, right? I'd probably
check these on and off when you first start flying it as well, just to be on
the safe side.

Jeff

[n85ae]

Do NOT flush the tanks with anything but gas, because if you do they likely
have Kreem in them and then you just opened Pandora's Box ...

Jeff

[beeryboats]

I'm all ears on this as my IV has been setting for TEN years! Mine looks like the header tank is half full, but I'm replacing that anyway. I assume as it's only half full the tanks must be empty. Is this false logic? I bought a 6' endoscope that plugs into a laptop just to see what's in the tanks.

[WWhunter]

I will not reccommend this for an aircraft, but I was overseas for several years and I had left gas in one of my tractors. To say there was nasty crap in the fuel tank would be an understatement. I am not sure where I read it or got the idea but I flushed the tank with "WORKS" which is Hydrogen Chloride. Less than $2.00/botle and I sloshed it around then rinsed it multiple time with water. Thuroughly dried it by leaving it out in the sun for a while, it looked like new inside. This was on an early 1950's Ford 8N tractor that had many years buildup.
I don't know if this chemical would destroy whatever material your tank is made out of but it does wonders on a steel tank. Even used it on and old motorcycle that had sat for 17 years.

[Lion8]

If you drain the 'bad gas' and refill with new gas, make it 100 Low Lead. Avgas will not go bad for a very, very long time. You can go to any local airport that sell 100LL with a couple 5 or 6 gallon cans and get them filled. The car guys do it all the time. Drawback? Pricy. Here in Southern New Jersey it is about 6:15 a gallon. You can still but it after you strain it real good.