I agree with the the first comment. It is the quality of the oil you are using that dictates how it is diluted. Handbooks give a ratio- especially supermarket type machines, which tends to be either 25:1 40:1 or 50:1. This is very dangerous as they cannot know exactly what type and quality of oil the end user is intending to use. Modern oils tend to be either semi or fully synthetic which means they give better protection than the old mineral oils, with less oil used in the mix which did require more to give protections, so generally 25:1 or maybe even 40:1 was the norm.
Always consult the recommended dilution ratio that will be clearly marked on the bottle of oil you are using. Avoid using cheap old style 2-stroke oil purchased from the sheds as generally they don't have any ratio marked on the bottle, and if you use an oil that is cheap with a 25;1 dilution ratio and you mix it at a 40:1 ratio then you will seriously under-oil your engine.
pleasant, May 2013
