R107 Exhaust Smell

[glenn911C4S]

My 300sl has developed a very smelly fumey exhaust, it really makes your eyes water. It’s done 123k and recently passed its MOtT. Any ideas?

[911Thrasher]

over fuelling...don't try to squeeze the extra .5litre

and fuel tank return lines: when they get old they become hard crack and let gases escape

both common