Glort, interesting stuff, and I agree completely about the overcomplication and parroted keyboard jockey garbage out there. Harping back to the black gunge, during a recent garage tidy I came accross 1/2 a pint or so of my sons stale r/c car fuel, methanol/castor oil/nitro blend, now this had several 1/8" -3/16" black globules in it, these I assume were clumps of bacterial growths. If these will form in a sealed container in what would be a very pure fuel ( is methanol hygroscopic ?) then who knows what will grow in used fryer oil ?
The problem in our (UK) winter with the more viscous alternative fuels is my assumption that stock size fuel lines and fuel filters will not allow sufficient flow at lower temps to allow the IP to operate correctly, compounding this is the fact that most vehicle engines here do not have a seperate lift pump and depend on the IPs internal vane pump to draw fuel, in higher mileage vehicles this pump can become worn and until diagnosed this can send you nuts with filter changes, suspected air leaks etc, am assuming your Merc has a lift pump an inline IP pump fitted.
Not too sure about the water injection, it certainly scours the top of the piston and causes pitting erosion in cast iron heads, I have seen this in a few engines that have had extended use with a cracked cyl head. In a diesel engine, apart from cooling the combustion temps I can`t see much point in it, what doesn`t go out the exhaust will end up in the sump.
Mark.
