Elfin Motors
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Everything you ever wanted to know about fuels and More

Everything you ever wanted to know about fuels and More.


Fuel Quality. One of the major maintenance headaches for small engines is fuel quality.  Fuel quality is affected by a myriad of factors.  Current day fuels have special problems due to the many formulations required by government regulation.  In order to meet mandated fuel requirements, refiners are faced with a large variety of recipes for their product.  They are required to provide fuels which change in characteristics due to, in part, time of year, altitude, location, etc. In order to meet these requirements, the base gasoline is blended with a variety of additives, most of which are quite volatile.  These additives are required to improve octane rating, control volatility, control oxidation and many more factors.  Most of these additives are themselves quite volatile and some are hygroscopic (they attract water).  These factors become significant when fuels are stored for extended times.  The longer fuel is stored the more of these additives tend to evaporate leaving the base gasoline. Others have time to attract water. With the loss of these components of gasoline it now becomes a serious problem as far as engines are concerned, particularly small engines. When the depleted gasoline is then burned during the normal operation of an engine it leaves serious deposits of carbon, carbon component products and varnish to name a few. These gummy and varnish like compounds then clog fuel system components such as; fuel passages, carburetor passages and jets, fuel lines  filters, injectors and valve train components. In small engines, these combustion by products are serious factors in failures which can be catastrophic.  Small engine valve systems are particularly vulnerable.  Large deposits of carbon impregnated gummy varnish compounds  rapidly build up in the combustion chamber.  These deposits typically foul the valve train components to the extent that valves, typically the valve stem/ valve guide interface are coated in sufficient quantity to jam the valve open, usually the exhaust valve.  When this happens it can cause extensive damage to the piston, cylinder head, valve, valve push rod, and cylinder or nay combination of the above. The rate of accumulation of these deposits is very rapid.  Engines have been damaged within a 15 minute time frame.  In most cases this deteriorated fuel is detectable by smell.  The smell of bad or skunky fuel is usually very strong and very unpleasant.  If this condition is evident, DO NOT RUN THE ENGINE. 


What can be done?


There are two conditions that present themselves.  The first one is the easiest to address.  There are fuel additives commercially available which condition and stabilize good fuel. These products are designed to prevent the volatile components of gasoline from evaporating. There are several brands available and should meet any requirements you may have.  These products are available from virtually any auto supply store and, of course, from Elfin Motors. The second condition is when you discover bad fuel in the fuel system.  There are NO products which will rejuvenate bad fuel.  As much of the fuel as is possible, must be removed from the fuel system.  Replace with fresh new fuel.  A good and prudent practice is to then replace the fuel with stabilizer treated fuel.





Define, Extended storage.


Depending on your geographic location and climate some fuels remain viable for as little as two weeks after they leave the refinery to typically six weeks after leaving the refinery.  Under normal conditions these time frames are not a factor.  Gasoline shipped to your local favorite fuel suppler are usually sold and burned well within the above time frame. However, lets consider the fuel typically used in small engine applications. Most small engines are used to power home or commercial lawn and landscaping maintenance products.  Lawn mowers, pumps, trimmers and other small engine powered equipment are typical. A large portion of this type of equipment tends to be seasonal in use, yard products in the summer and snow removal products during winter.  If this equipment is stored away after its seasonal use without stabilized fuel there will be problems next season.  Also consider how a typical fuel purchase takes place.  We take our trusty fuel container over to the gas station at the beginning of the season and fill it with new fuel.  Then it is taken and stored in the garage or shed and it is dispensed as need all thru the season.  Most summers and winters tend to be longer than six weeks.  Therefore if the fuel is not treated with stabilizer additives we set our selves up for problems.


In addition to the skunky fuel problem there is water.  Those of us who have worked at Elfin Motors for several seasons have yet to find an engine that will run on water. If someone out there has achieved this please contact us so we can share in your good fortune.  Having said that, the question is, how do we get water in the fuel system?  Generally there are two ways water finds itself in fuel.  The most common is from our trusty fuel can we have been using for the few pasty years. Fuel cans will collect water from two sources. One is, the fuel supplier may not be really careful with  the care and maintenance of his tanks and filters. The other is condensation.  All fuel containers will collect water from condensation normal to climate changes.  Plastic containers are less susceptible to condensation than metal containers but they will, none the less, collect water.  Metal containers are also the source of solid contaminants such as rust. The other source of water is condensation within the fuel tank of the equipment itself, which if it is metal the solid contaminants are also possible.


In conclusion


Elfin Motors recommends the following to reduce the effects of fuel related problems in small engines. First; Always use fresh clean stabilized fuel.  Store your clean fuel in a cool shady place.  Be aware of water contamination.  In addition to the sources motioned earlier, there is rain, sprinklers, snow or any other form of precipitation to which your equipment may be exposed to.  Keep fuel containers and fuel tanks topped off during storage to reduce tank condensation.  If these guide line are followed you will most likely eliminate fuel related failures.