15-11-16, 10:49 PM
Interesting thread some good tips. I've had water dripping into the tank too through the filler cap. It's made the key lock difficult to turn and turned the inside a bit rusty.
I now always fill at a BP garage where I know they stock the soft paper towels which I use to soak up as much moisture as I can when I fill 'er up in wet conditions. A smear of petroleum jelly around the lock, seal and lip seems to have kept the worst of it at bay.

Treat everything in life the way a dog would- if you can't eat it or foc it, forget it.