Sierra 18-99390 Trigger Assembly for Mercury 50HP 4-Cylinder Outboard

The Sierra 18-99390 is a replacement trigger assembly designed specifically for Mercury 50HP 4-cylinder outboard engines. This critical ignition component works in conjunction with the stator and switchbox to generate the timing signal that fires the spark plugs at the proper intervals.

Key Features:

• Direct replacement for Mercury marine trigger assemblies
• Precision-engineered to OEM specifications for reliable ignition timing
• Designed for 50HP 4-cylinder Mercury outboard applications
• Quality aftermarket ignition component from Sierra, a trusted name in marine parts
• Helps restore proper engine starting and performance

Sierra marine parts are manufactured to meet or exceed OEM standards, providing boat owners with a cost-effective alternative to original equipment parts. This trigger assembly is essential for maintaining proper ignition system function and ensuring reliable engine operation.