Solenoid | Sierra 18-5815 Sierra Solenoid | 18-5815 Isolated base 12 volt starter solenoid and tilt & trim solenoid for many Mercury and Mariner outboards. Isolated base 12 volt Replaces Mercury 89-853654A1, 89-68258A4, 89-15857, 89-68258, 89-61053, 89-76545T, 89-76545, 89-853654B1, 89-68258B4 Replaces Mallory 9-15111