It smells petrol

There are usually short pieces of flexible hose in the fuel line, often buried behind the engine, I think they are there to allow for engine movement, they perish with age and continuous flexing and are a common source of fuel leakage/seepage. It's not unknown for them to cause starting problems since the fuel pump starts sucking air, and, at the relatively low cranking revs, not enough fuel to replace that which has drained away. If the engine starts it's higher speed then pulls an adequate fuel supply.