Even if I do not have time to lay out all that I know about long-term storage of various fuels and the various types of engines that might consume that fuel, perhaps I can pass along some helpful information.
As a rule of thumb, I figure I’ll need one gallon of chainsaw gas for every one cord of wood that I cut, and I’ll need half that volume in bar oil. If we can keep a chainsaw running, then that fuel could be of adequate quality to run anything else. Gasoline is much more difficult to store than diesel, and if we can successfully store gas that meets the higher standard needed to run a modern chainsaw, then we can run anything else with that gas. However, we could also go electric and run a diesel generator to charge an electric chainsaw, but I simply do not have the excessive wealth for that option at this time. Another way is to have a large enough PV array to charge an electric chainsaw. If I could, my first choice in an electric saw would be a Makita, yet as it is, my best choice is an old school, slow and heavy 35 year old saw that I believe is a better choice as it can run on lower octane fuel and a variety of 2 cycle engine oils, even 30 weight motor oil in the fuel in a pinch. But then most already have a modern chainsaw, and so do I, so we’ll need fuel for these.
The old, slow, and heavy saws have their virtues. The most noteworthy is that in a long-term collapse scenario, it can run on low octane fuel that might harm a modern saw. Unfortunately, it would be difficult for the average person to locate or repair an old school saw, so they must contend with the fuel requirement of modern lightweight, and high-performance saws. The problem for modern saws is its requirement for high octane gasoline. Without that, the engine can overheat and become damaged. If you run a modern StIhl saw on low octane gas, or even with fresh premium fuel with too much 2 cycle oil in it, the octane rating is too low. When run hard and hot, one might hear pre-detonation (knocking) in the cylinder that can burn a hole in the piston over time, or immediately. These are high-performance machines, akin to a Formula One race car. There is little tolerance to less than ideal fuels and lubricants. My old school saw is more like a tractor in comparison. It is harder to use, but keeps on plowing through wood, decade after decade with whatever I put into it. The brand and model of my old saw is not important, it is the technology that is used in these saws that is important. Currently, I am running 2-year-old untreated (not stabilized) premium non-ethanol fuel it with a 32 to 1 ratio mix of TW3 rated 2 cycle oil that is not recommended for modern chainsaws. This fuel would not work well, and would probably damage a modern saw and certainly degrade it’s performance. Old school saws are much less ‘picky’ in other ways as well. I have gallons of TW3 type 2 cycle oil intended for water-cooled 2 cycle engines that I got for free. It is higher grade lubricant than was available when the old saw was made.
A modern saw should use a 50 to 1, or a 40 to 1 mixture with a synthetic lubricant for best performance and longevity. Stihl requires 50 to 1 and premium fuel. It is also important to use non ethanol premium grade with an octane rating of 91. Because the ethanol is hydrophillic, and water can be absorbed into fuel during storage. Water suspended in the fuel by the ethanol does not mix well with 2 cycle lubricating oils, and damage can be done to the engine. Water can also accumulated in any fuel tank or container. When filling the saw fuel, always leave about an inch of fuel on the bottom of the gas can to avoid putting water that is at the bottom of the fuel into the saw. Any water in the fuel could quickly damage the piston and cylinder wall. Benzine, not the ethanol can do damage by shortening the life span of the diaphragm in chain saw carburetors. Have several replacement complete carburetors. Gasoline from the 1960s and 1970s was closer to pure gasoline. Old school gasoline did not have near the list of additives, such as olifins that gum up works, and other additives. As time progress, more additives were added for various reasons. The diaphragm is the fuel pump for the saw. Using gas that does not harm the diaphragm, or plug up the very fine orifice inside these tiny carburetors improves reliability and performance. Also octane rating becomes lower as the stored fuel degrades in general. Oxygen is the primary enemy of gasoline. If the can breathes, or is permeable to oxygen, as are plastic storage containers, the rate of degradation increases. Swings in temperatures cause not only condensation, but more import, unacceptably high internal pressures that may cause essential light violate gases to escape containment.Continue reading“Chainsaw Fuels for Long Term Storage, by Tunnel Rabbit”
