A sad sight, one of my favourite cars
They suffer from lack of use, with the V12 they have a bank of Twim Weber Carbs (IDL's, I think)on top of the engine. The floats stick down and flood the engine and overflow out the top of the carbs onto the manifold if they've not been run in a while. Early cars had no return, so flooded if sat at idle too long. The car in the film is an SV, so it should have the redesigned fuel return.
I bet, this is what happened. If you listen to the guy talking he says it's been running all morning but having trouble when he tried to pull away. This is classic over fueling of one or more cylinders.
Unfortunately it's a sad case of those having the money to own these cars with no basic car knowledge. It's a damn crime to allow these idiots loose with a Miura. I can't believe they didn't have a fire extinguisher or even make an attempt to find water or anything to put it out. Hell if it were mine I'd strip off and beat the flames out with my trousers if I didn't have an extinguisher, not just stand and film it like a prize muppet.
God it makes me so angry that morons have these cars
