I had something very similar about 10 years ago, turned out to a crack in the distributor cap. Near invisible when cold but once the engine had warmed up it opened up! Might be worth checking!
The smell of fuel may be the accelerator pump diaphragm failing - on my 1972 4/4 (with a Weber DGV), you could see a small drop of petrol leaking when a helper pressed the accelerator pedal. New diaphragm comes with the genuine Weber/Webcon service kits
Cheers
Arwyn
