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Content taken with permission form the QINETIQ report (makes for interesting reading)

We have started to see the problems with Ethanol in the ultrasonic carb cleaning section of our business

Ethanol in fuel.

 There is concern in some corners, especially among the owners of classic and older machines, that the enforced introduction of ethanol in blended fuels will have a detrimental effect. The following will help answer some questions about what is ethanol and why are we getting it.


* The addition of ethanol to petrol is being driven by the oil industry (globally), the automotive industry - and the European Union

* Standard pump petrol can contain up to 5% ethanol without being labelled, in future it could contain up to 10% ethanol ("E10")

* An estimated 2 in every 3 litres of petrol contains (4-5%) ethanol

* Ethanol can be highly corrosive to many materials used in engines/fuel systems and can cause other problems

* c.769,000 bikes may be incompatible with E10 fuel, although many manufacturers' bikes have been compatible since the mid-1990's


The question of ethanol in petrol is being driven by the fuel industry (globally) and the European Union. The fuel producers have worked with the car and commercial vehicle manufacturers over several decades to agree a feasible timetable that would allow the fuel producers to introduce more ethanol to road fuels and for the vehicle manufacturers to phase in replacement vehicles capable of handling higher concentrations of ethanol. The EU has set standards and policies that member states must adhere to (although again this seems largely driven by the oil industry). In short, a global agreement by very powerful industries has played in to a political agenda about environment/sustainability (and to a lesser extent, securing future fuel supplies) that effectively sidelined users of older vehicles.

Bioethanol for fuel is derived from crops rather than pumped out of the ground, so is said to be a sustainable resource in that it won't run-out in the same way as oil; this makes it economically more attractive. However, it can be highly corrosive to many materials used in vehicle fuel systems and can both hot and cold running problems. Typical problems include;

* Fuel filter blockage and increased wear of fuel system components: Ethanol acts as a solvent loosening abrasive deposits

* Galvanic corrosion: Ethanol is more highly conductive compared to hydrocarbons leading to corrosion if electrically dissimilar metals are present in the fuel system

* Air/Fuel mixture problems: Ethanol contains about 35 % oxygen, so the air/fuel mixture has to be adjusted otherwise the vehicle will run lean which could cause drive-ability problems and overheating

* Drive-ability: E10 blends can be more volatile, causing hot problems (poor hot starting, hesitation etc) and cold weather problems (vaporisation problems)

* Deposit formation: Inlet system and combustion chamber deposits have been reported with the use of E5 and E10 blends compared to E0.

* Material compatibility: Some materials used in fuel system components are less compatible with ethanol in fuel resulting in loss of structural integrity, swelling and softening of materials (some older glass-fibre petrol tanks and tank sealants will melt).

* Ethanol holds more dissolved water and associated impurities leading to corrosion of metallic components.



There are two relevant items of legislation covering the UK:

The Renewable Transport Fuel Obligation (RTFO) currently requires that within the total volume of road transport fuel supplied, the proportion which is biofuel (incl. bioethanol petrol, biodiesel and biogas) will reach 5% by 2014. The EU Renewable Energy Directive (RED) requires all member states to ensure that the share of energy from renewable sources in road and rail transport using petrol, diesel and biofuels is at least 10% in 2020.To that end, EU directive 2009/30/EC increases the maximum permissible content of ethanol in petrol from 5% to 10% (shown on petrol pumps as 'E5' and 'E10').


The UK government says this need not mean that all pump fuel should contain biofuel, that is being left to the fuel supply and retail industries to decide. On the other hand, nor does UK government policy require that non-ethanol fuel should be widely available on forecourts. The Federation of British Historic Vehicle Clubs (FBHVC) have more information on the subject.

The Department for Transport commissioned an independent report in to the effects of E10 on existing vehicles, the report

recommended the following:

* Vehicles ten years old or older, carburettored vehicles (including powered two wheelers) and first generation direct injection spark ignition vehicles should not be fuelled on E10 unless the manufacturer can state the vehicles are compatible with E10.

* The automotive industry should produce a comprehensive list of vehicles compatible with E10. While it is acknowledged that some lists do already exist if in doubt the vehicle operator should seek clarification from the vehicle manufacturer.

* E5 should not be phased out in 2013, its widespread availability should continue for the foreseeable future.

* Consideration should be given to maintaining a specification for E0 fuel for historic and vintage vehicles.



There are standards in place for the composition of petrol containing bioethanol. These are important for consumers, but also for the supply/retail industry as storage tanks and other equipment can also corrode if exposed to high concentrations of ethanol. However, at levels under 5% the retail pumps are not required to be marked as dispensing fuel containing ethanol. Article 21(1) of the RED requires that where transport fuels (for all modes of transport) contain more than 10% biofuel by volume this should be indicated at sales points, however these fuels are not currently intended for supply to the public. The UK government has asked CEN (Committee European Normalisation) and the EU to establish a consistent labelling system in anticipation of the time when they are available on the forecourt.


The Qinetic report for DfT found current (2010) usage of ethanol in petrol in the UK is low (equivalent to 2.8 % of total unleaded petrol sales in 2010) and that although the coverage is widespread it is not uniform "Typically petrol contains either no ethanol or 4 to 5 % depending on the geographical area." (NB: HMRC figures for March 2012 show the quantity of petrol generated from biomass was 3.3% of all petrol, suggesting less than two-thirds of pump petrol currently contains ethanol).

The same report gives an overview of bike manufacturers' information about E10 compatibility:

  • Triumph motorcycles have been compatible with E10 since at least 1994. From 1993 to 2008 nylon moulded fuel tanks were employed but due to vapour permeability concerns a switch back to steel tanks was made.

  • BMW motorcycles have been E10 compatible for at least twenty years.

  • Harley-Davidson motorcycles have been E10 compatible since the 90s.

  • Kawasaki are still considering the effects of E10 and do not recommend its use.

  • KTM models from 2000 are compatible with E10.

  • Yamaha models are compatible with E5 and some new models are compatible with E10.

  • Suzuki's have been compatible with E10 since 2005.

  • Honda models have been compatible with E10 since 1993 but carburettored vehicles could suffer poor drivability.

An importer of powered two wheelers from China said the factory made no provision for the use of E10 and expects material compatibility problems with these vehicles if they are fuelled on E10.





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