Where ?on what?
Mostly on a belt driving something
probably being over used and the rubber inside is burning and melting....
Usually that means he/she has been under a car.
sounds like your air conditioner compressor is bad.
Rubber
You can use either term. 'Burned' and 'burnt' are variations on the same word, just like 'learned' and 'learnt'.So you could say, 'The car smelled of burned rubber', or 'The car smelled of burnt rubber'.
Crack has a very sweet smell, like burnt marshmellows.
burnt clutch will smell something like burnt brake pads.. usually clutch disk have semi metallic pads
Like Rubber
it could be from your valve gaskets leaking oil. my car was smelling like that and my gasket seals were leaking, both front and back. after having them replaced i dont smell it anymore. KNOCK ON WOOD
Similar to burnt candy or something sweet that has been burned. It is a very unique smell that can't really be described.
like a condom or rain coat
Varnish, or in other words it does not smell like gas, it smells almost burnt