Do you mean the heavy, short machined pin with the tiny hole through it that actually connects the cable to the throttle lever, or the tiny cotter pin that fits through that tiny hole to retain the short pin? A cotter pin looks like a hairpin - doubled over, and you spread the loose ends to keep it from falling out.
In the UK the thing you describe as a cotter pin is known as a split pin.and the pin it goes in is called the cotter pin! just to confuse matters.
But in saying that I still dont know which one andy requires :wave:
Andy!! Big pin, LIttle pin???????