Beware of storing two-stroke mix…

I have always thought of myself as pretty analytical, yet something simple, but very easily overlooked, has twice caused me problems which I could have avoided. This something is the oil which is added to two-stroke fuel, or rather the life expectancy of the lubricating part of the mix.

You might think I must be a bit dim to be caught out twice, yet the first time I had problems when my outboard overheated and seized, I put the problem down to a damaged impeller, which I replaced. Unfortunately it seized when I needed it most, for like many dinghy cruisers, I prefer to avoid the noisy item, however being late for a tidegate and being in a position where sailing was not possible I was relying on every one of the four slightly lame horses. Well, I survived, but was a little chastened by the result my reliance on what I now saw as a very unreliable machine.

I bought a six h.p. motor a couple of years later, which I still have and which runs like a watch. However, early last April on my first trip of the year, motoring away from my mooring against the wind, the motor gave that pained strangulated sound which I knew meant it was not well. The smoke rising from the casing was another clue! I immediately thought that I had not put oil in the mix. This was a possibility as I had bought the fuel in October, so I chucked in the required amount. Result; peace restored, and the motor purred away. On returning home I found that I had not made a mistake, and the fuel in the tank, which had been stored in the cool and dark, had had oil in it. The mix was five months old and I have often started the season with some ‘old’ mix. Something significant began to bore its way into my head. Was this related to my unpleasant experience a couple of years before?

Now, I was under the impression that six months was the life of two stroke mix, in fact I remember that was the life expectancy for correctly stored fuel given by someone from the oil industry in an article I read last year. I now realise that this is often not the case, and I had been using a different brand of oil. This will of course not come as a surprise to some members who have either thought a lot about it, or learned the hard way like me. But I write this for all those of you out there who have experienced mysterious overheating problems and similar, or who may suffer occasional memory dysfunction. Don’t risk it. Buy some fresh fuel and best quality oil — use your old stuff in the strimmer with a bit of extra oil thrown in.