Hi John,
Funny you should mention that about a Dingo carb. I have been working on a Dingo, not used for a while, petrol was "dead" and smelly and it would not start, fresh petrol and away it went. Now my Bedford stands all winter and starts as good as ever after 6 months, on stale petrol, so I have come to the conclusion that some carb types can influence petrol problems.