Thread: which 50-60cc Stihl chainsaw

Yep, oil has a higher calorific value than petrol (i.e. produces more heat when it burns). The density of the fuel makes a marginal difference to carb fuel metering, as does but to a lesser extent things like altitude and to a greater amount air and engine temps. The actual amount of oil in the mix is one of the lesser factors, by that I mean the difference between 50:1 and 40:1 ratios is less than one percent change in the brew. That doesn't really equate to anything weird for engine running, and as another example leaving a can of fuel in the sun to heat up and using it hot produces more of a density difference when compared to running the same fuel on a cold morning with the can temperature as low as you'd get.