Why you don't need to 'reset' your premix

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Phil Bate
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Why you don't need to 'reset' your premix

Post by Phil Bate » Thu Jun 19, 2014 1:29 am

I often hear people suggesting or asking if you should not premix on the occasional fill-up, to prevent the ratio of 2T gradually increasing. An understandable assumption, as there is always a bit of 2T oil left in the tank before you add yet more.

However if you think about it, as long as you always add petrol and 2T at your chosen ratio the mixture in the tank will remain close to this, and even iterate back towards it after the odd skipping or overdosing of 2T.

Have a look at this table:

premix_iterator.png

It calculates how much 2T per litre of petrol your tank would contain after filling with given amounts of each. It starts with a non-premix fill, then from then on follows a typical 125ml per tank regime with a few curve balls added, like a 20litre non-premix get-you-home, and a higher than normal dose amongst less radical variations.


As you can see the ratio always works back towards around 440:1 if you follow an average 125ml shot per 55L fill-up. So as long as you target a certain amount per tank and adjust this accordingly (i.e. half as much 2T for half a tank fill etc.) then you will not eventually end up with a tank of pure 2T oil :)
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