As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING A PRE-FLIGHT RUN-UP THE AIRCRAFT ENGINE LT MAGNETO DROP WAS 600 RPM. TROUBLESHOOTING SHOWED THAT THE CAUSE WAS A FAULT WITH THE SLICK-START MEGNETO BOOSTER. THE BOOSTER WAS REPLACED AND THE ENGINE GROUND RUN. THE MAGENTO DROPS WERE WITHIN LIMITS.