RE: My Fuel blamed for Rust
Many of the fuel manufacturers claim to add rust inhibitors. Do these help - I do not know. I suspect your problems may be more due to not using after-run oil and not getting all the unburnt fuel out at the end of the day. Just pulling the fuel line will not do it. You must put the glow plug ignitor on and turn the engine over until it no longer fires.
In the "good old days", many of us used to run our engines on castor based fuels - never used after run oil, never fully got all the unburnt fuel out - and had no rust problems. Just go figure?!
Paul