Mercury - Quicksilver 819503A4 Solenoid Kit Mercury TwoStroke & Jet Outboards 819503A4. Overview. If your motor hesitates when you turn the key, chances are it's your solenoid. The Mercury 819503A4 Solenoid Kit brings back reliable, quick starts for Mercury TwoStroke and Jet outboards. It's an exact OEM replacement built for performance and durability - tested to handle salt, heat, and vibration without losing contact or power.. This kit fits a wide range of engines, including V135-V200, 140 Jet