Metal Gas Tanks and Ethanol

exmarDecember 21, 2011

Hi folks,

OK, we're all familiar with ethanol being detrimental to small engines as small engines tend to sit with fuel in them. This leads to water build up, carb jet issues, etc. Another issue with small engines and ethanol is the older engines tend to have metal gas tanks which do not like water. I discovered this in a roundabout way while restoring a '74 JD tiller with a H60 Tec with a metal gas tank. Inside of the tank was a disaster and I researched gas tank coatings. Discoverd that there are posts on other forums that ethanol (alcohol) attacks some coatings. Sent an email to POR and asked them. They responded that their product is tested with 100% ethanol with no problems. They also suggested they have an additive which is formulated to offset this problem.

This led me to look at some of my other old engines with metal tanks and was not happy with what I found. I guess I'm going to be doing some cleaning, coating and cursing this winter.

Not a Shill for these folks, never used these products, but was impressed that they're aware of the problem and have done some testing.

I've attached a link for the fuel preservative. The tank coating is also there if you look around. amazon seems to have the best price.

Just sharing,

Happy Holidays!


Here is a link that might be useful: POR fuel preservative

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Some people suggest flushing the tank with CLR then rolling it around with some MMO to keep the rust away. I was about about to do this to my 40$ snow blower rehab. But I found a good tank. The drill with metal tanks is to keep them full when storing. That advice pre-dates ethanol fuel. Also . I use MMO . but if you store a full tank, you prolly should use a stabilizer.

    Bookmark   December 22, 2011 at 8:30AM
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Tanks have always been stored, full with stabil. Stopped doing this a couple years ago due to ethanol concerns. e.g. tillers which will sit for 5-6 months during the winter.

Read an interesting observation on another forum, "I've never seen a chain saw or other two cycle tank rust." Thinking about that, neither have I and I've got some old saws. MMO or "generic" two cycle oil may be the answer.

Guess adding a fuel shut off so the engine can be run dry while leaving gas and oil in the tank may be of use.

Just don't want to have to try and replace 30+ year old gas tanks....:-)


    Bookmark   December 22, 2011 at 12:07PM
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My '76 Stihl chainsaw has a die cast aluminum gas tank. So no rust.But, the rich mix I use lets me use my pre-mix until the jug is empty. It does run a little smoky towards the end, but it runs. 2 stroke oil in a 4 stroke is fine. Some guys run it instead of MMO. All I know is that using MMO and shut offs, keeps my old stuff going better than not using them did. The way I look at it is, the old junkers I run were designed to run on leaded gas. Running unleaded is tough enough on the old stuff. Let alone lead free with 10% ethanol in it. Best to give them something to make them run a little easier.
Sorta like sugar cubes for a good horse. :)

    Bookmark   December 22, 2011 at 7:27PM
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Ex: I have used POR on a few automobile frames 1985 Jeep CJ-7 Larado and 1972 Dodge Power Wagon 4x4 . This paint and sealer were top notch for these restoration applications. If they advertize it willl perform then it will . As for chainsaws most tanks are cast Alluminium or Magnesium. I recall a few Macs back in the early 60's with stamped steel cylindrical exterior tanks . I have pretty well resolved myself to Star*tron for all preventative measures as to fuel issues. Seaform or MMO perhaps for oil Therapy Additive usage on older 4-stroke vintage units. Although Stabil did the trick for me for yrs using one product for multiple useage simplfies the task and the consumption is far less with Star*tron I find. Thanks again Raystrom :) .

    Bookmark   December 23, 2011 at 10:28AM
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Good info, thanks. I also used SeaFoam for years, wonder why it got so expensive recently? Good point on the saws, must admit haven't really examined them to see what's what.

I researched Startron and am impressed. It initially seemed pricey, but since 1 oz treats 16 gallons of gas it'll go a long way. Let's see, that would equate to about 10ml (or cc's) in a 5 gallon can. I can see "and the consumption is far less..." that you mention. A 16oz bottle will last me a long time. It goes on my "to buy" list.

Will probably continue to add a "little" MMO to gas on fill ups as I also add a "little" STP oil treatment to the oil if needed between oil changes. Probably doesn't do a lot of good, but doesn't hurt either and I've been doing it for a lot of years.

Thanks again,


    Bookmark   December 23, 2011 at 12:35PM
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Ex: Were on the same page Bro ! Thanks for the note of confirmation . All the Best to You and Your's This Christmas Season :)

    Bookmark   December 23, 2011 at 5:57PM
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