Willy, where are you getting power for the flasher? I think the only way it could affect the engine is if it's hooked to the ignition circuit instead of an accessory power point
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics