Maintain Proper Air/Fuel Ratio
Here's an invaluable tool for precise engine tuning. This indicator features an exposed junction thermocoupler for instant response, a hold button for recording measurements, and the abilities to record the maximum temperature reached and to monitor two cylinders at once. It includes a tough rubber, molded case and a temperature probe for reading fuel, manifold, or head temperature.

Percy's also offers kits and components to withstand the harsh RF signal enviroment commonly associated with magneto ignition systems.