Gasoline also known as petrol outside North America, is a transparent, petroleum-derived liquid that is used primarily as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives.
On average, a 42-gallon barrel of crude oil (159 L) yields about 19 US gallons (72 L) of gasoline when processed in an oil refinery, though this can and does vary based on the crude oil source's assay.
The characteristic of a particular gasoline blend to resist igniting too early (which causes knocking and reduces efficiency in reciprocating engines) is measured by its octane rating. Gasoline is produced in several grades of octane rating. Tetraethyllead and other lead compounds are no longer used in most areas to regulate and increase octane-rating, but many other additives are put into gasoline to improve its chemical stability, control corrosiveness and provide fuel system 'cleaning,' and determine performance characteristics under intended use. Sometimes, gasoline also contains ethanol as an alternative fuel, for economic or environmental reasons.
Do not wait to repair the car
Minor repairs of the car does not usually require a lot of time or money. Often, however, we ignore this type of failure - after all, they are not dangerous, and nowadays many people find it difficult to find even a brief moment to drive the mechanics and to verify the minor faults. Of course, this is a mistake. Few serious problem, which will be mishandled, could adversely affect other mechanisms and systems of the car. So if the failure is not remedied, it is likely to contribute to a much larger damages, and hence - the cost of repairs will increase significantly. Often in such a situation replacement parts are required, which of course affects the final price of the service mechanic. Not so it is worth delaying the service of the car, even if the problem with him seems to be harmless.
Larger two-stroke engines
An example is lubricating oil for four-stroke or four-cycle internal combustion engines such as those used in portable electricity generators and "walk behind" lawn mowers. Another example is two-stroke oil for lubrication of two-stroke or two-cycle internal combustion engines found in snow blowers, chain saws, model air planes, gasoline powered gardening equipment like hedge trimmers, leaf blowers and soil cultivators. Often, these motors are not exposed to as wide service temperature ranges as in vehicles, so these oils may be single viscosity oils.
In small two-stroke engines, the oil may be pre-mixed with the gasoline or fuel, often in a rich gasoline:oil ratio of 25:1, 40:1 or 50:1, and burned in use along with the gasoline. Larger two-stroke engines used in boats and motorcycles may have a more economical oil injection system rather than oil pre-mixed into the gasoline. The oil injection system is not used on small engines used in applications like snowblowers and trolling motors as the oil injection system is too expensive for small engines and would take up too much room on the equipment. The oil properties will vary according to the individual needs of these devices. Non-smoking two-stroke oils are composed of esters or polyglycols. Environmental legislation for leisure marine applications, especially in Europe, encouraged the use of ester-based two cycle oil.