Exhaust spark plug

[jreacock]

Someone sent me a pic today, showing a spark plug in the exhaust of a Stratos. I thought I'd seen most things, but maybe I've led a sheltered life. Is un-burnt fuel going through the exhaust such a big deal? It would be for a cat I guess, but that's not the case here.

[sdebez]

Posted on here from another thread, most have assumed its the blanked of Lambda sensor.

Probably used the spark plug, because the thread isn't your usual bolt size if it needs blanking off