richlist wrote:Why would the fuel damage the same plastic tank over the same period of time during the summer ? My plastic tanked mower has a virtually full tank of fuel from March until September.
In the case of the Ducati fuel tanks, the tanks were constructed from a blend of plastics which chemically reacted adversely to the ethanol. Specifically there was a nylon in the the formula which when exposed to ethanol, quite quickly began to deform and in some cases split. This led to a legal claim in the US which resulted in a recall. As is often the case, Europe didn't have the legal case and plenty of late 90's/early 2000 bikes still have the issue.The issue is not specific to bikes, many reported failures occurred on boats where the fuel tanks are often made of glass fibre, which led to highly dangerous fuel leaks. This all in addition to the degrading of fuel hoses and O ring seals. I suspect that your mower is probably fitted with a polyethylene tank since that is a common plastic used where aesthetics are not a big concern. Polyethylene is impervious to ethanol. Your tank is full from March to September and the fuel is used and replaced, so the gunge issues won't occur. Its only if you leave fuel in the tank in damp/cold conditions where the fuel can combine with moisture condensing from the air that the gunge problems might occur. The fuel stabiliser is a good fix for mowers over winter.