During operation of a spark ignition engine, an ignition system produces an output (e.g., breakdown voltage, peak secondary coil current, and spark duration) used to combust a charge (e.g., mixture of air and fuel) in an engine cylinder. Ignition output is important to consider in engines including a second fuel with high ignitability, for example in engines with a fuel reformer system. Example methods, devices and systems are included for adjusting ignition output.