Methanol attracts moisture naturally, so the older it gets, the more moisture it has. I personally add castor to any fuel I buy, just for the security. I can get fuel made locally and its very fresh. Any mixture content I want, he will mix. Also, it can be work, but if you open, clean and oil the engine, you will most likely avoid corrossion and premature wear. If I find surface corrosion, I tear the engine down, and brass wire brush off any rust or corrosion. Those rust particles will come off and wear the internals of the engine. Its just like sucking in dirt, just metal dirt instead. Just my .02 cents.