Mogas - Technical Question
I tried this one on the LAA Forum but did not get any specific technical answers. I'm not interested in a debate on the merits of Mogas versus Avgas.
After a moderate period without use (six weeks), my VW engine was hard to start and ran roughly. Careful inspection of the carburettor revealed small, soft yellow/brown particles roughly the size of small sugar grains inside. There was also a yellow/brown residue on the ends of the needles.
The engine has been run on Mogas (with occasional Avgas).
In so far as I am aware I have not used fuel with alcohol in it, but is it possible that undetectably low levels of alcohol have caused the problem? The fuel system is all constructed from supposedly alcohol resistant materials but the tank is GRP. There does not appear to be any vissible sign of damage or decay in any of the fuel-system componenets.
On local expert tells me the yellow gunge is a corrosion product from zinc based cast carburettor-body and additives in the fuel. Is this possible or likely?
Can any of the fuel-experts on here provide a proper technical explanation of what is going on?