Sierra 18-2140 Engine MerCruiser Mount Bolt Kit

Sierra 18-2140 Engine MerCruiser Mount Bolt Kit is an application-specific marine replacement hardware kit designed to secure the front engine mount configuration on MerCruiser I (original pre-alpha, before 1983) sterndrive engines. It serves as a direct interchange for the GLM 21811 bolt kit

Kit Specifications & Contents

• 18-3729 Motor Mount Bolt (1)
• 16-0681 Primary Washer (1)
• Additional Washers (2)
• Lock Nut (1)
• Spacer (1)

Installation Insights

When replacing your engine mount hardware, keeping these critical installation practices in mind ensures longevity and safe operation:

• Support the Engine: Always use an engine hoist or heavy-duty jack stand to fully relieve tension from the front mount before extracting the old hardware.
• Surface Preparation: Thoroughly clean the mounting bracket and mating surfaces to remove rust, scale, or residual thread-locker.
• Lubrication & Torque: Apply a marine-grade anti-seize compound to the new steel bolt. Torque the assembly to the manufacturer's recommended specification, which typically sits between 25–40 ft-lbs for these blocks.
• Component Inspection: Take this opportunity to check your rubber mount isolators; cracked or sagging rubber will cause rapid hardware fatigue and excessive drivetrain vibration.