- paul-ryan.info Normal: light browncolour. Dirty: powderydeposits. Black carbon: anover-rich mixture, ortoo much choke. Oil fouling: worn valves orpiston rings. Pre-ignition: causesthe inner electrode tobe burned away.
Download

Appears in

Cleaning and fitting spark plugs

Pull off the lead by its cap. Clean away dirt from around the plug with a soft brush. A...