*im an EA owner, I've never worked on an ef.
are you sure its a fuel problem? My mates VL (dont worry fellas, hes going to buy an ef soon lol) had a problem with the mixture being too rich, we had to fix a seized choke (or "air regulator" as the manual calls it). check your sparkplugs to make sure, we went barking up the wrong tree with fuel filters.
if it is indeed the fuel filter, perhaps there is another after-market filter that has been installed later or earlier in the fuel line. other than that you could try running injector cleaner through it.im presuming its got an LPG conversion and never gets run on petrol lol.
maybe someone else can help you with the EF fuel tank draining.