Description

The Mercury MerCruiser Quicksilver 10-34353 is a genuine Mercury Marine OEM hex head screw used as diagram-specific mounting hardware on select MerCruiser engines, sterndrives, accessory brackets, pulley assemblies, seawater pump mounts, alternator brackets, and related engine hardware locations. This fastener is used where the Mercury/MerCruiser parts diagram specifically calls for 34353 / 10-34353.

Key Features

• Genuine Mercury Marine factory OEM hex head screw.
• Mercury/MerCruiser part number: 10-34353.
• Manufacturer/base part number: 34353.
• Thread size: 3/8″-16 coarse thread.
• Length: 1.00 in.
• Standard hex-head cap screw style fastener.
• Used in select MerCruiser engine, bracket, pump, pulley, and drive-related assemblies where specified by diagram.
• Suitable for replacing missing, corroded, damaged, rounded, or incorrect hardware in factory-specified locations.

Engine Compatibility

Common application context includes select MerCruiser gasoline and diesel engines by serial number and diagram location, including:

• MerCruiser 120 / 140 / 2.5L / 3.0L inline-4 applications where specified
• MerCruiser 4.3L / 4.3LX / 4.3LH V6 applications where specified
• MerCruiser 5.0L / 5.7L / 350 MAG / 350 MAG MPI small-block V8 applications where specified
• Select Alpha and Bravo engine package accessory mounting locations where specified
• Select big-block MerCruiser applications including 330 HP, 340 MIE, 370 TRS, 400 TRS, and 454 MAG MPI where specified
• Select D7.3L D-Tronic 300 diesel applications where the diagram calls for this fastener

Use this screw only where the Mercury/MerCruiser parts diagram specifically calls for 10-34353 / 34353.

Serial Number Fitment Notice

Confirm fitment by engine serial number, assembly diagram, bracket location, thread size, bolt length, and required fastener grade before ordering. MerCruiser engines often use similar-looking screws in different lengths, thread pitches, coatings, and strength ratings depending on the accessory bracket, pump housing, pulley, alternator mount, or engine block location.

When This Part Needs Replacement

Replace this screw if the original fastener is missing, seized, corroded, stretched, rounded, cross-threaded, or no longer clamps the component securely. It should also be replaced if incorrect hardware was previously installed, especially on accessory brackets, pump mounts, pulleys, and engine-mounted components exposed to vibration and heat.

Installation Notes

Verify the mounting hole threads are clean and undamaged before installation. Compare the removed fastener to the replacement screw for thread pitch, length, head style, and shoulder/contact area. Use the correct Mercury service manual torque specification for the exact assembly location. Do not substitute a longer screw in blind holes, as it can bottom out before the component is properly clamped.

Alternate/Superseded Part Numbers

• 10-34353 — Mercury/MerCruiser formatted part number
• 34353 — Mercury/MerCruiser base part number
• F1867 — earlier factory reference; verify by diagram and application
• F2202 — earlier factory reference; verify by diagram and application

Parts Desk Insight

Small engine fasteners matter because length, thread pitch, coating, and strength rating affect how the part clamps under heat and vibration. For brackets, pulleys, alternators, and seawater pump mounts, matching the factory hardware helps prevent loose components, misalignment, broken brackets, and repeat service issues.

Shipping: Ships same or next day for fast Canada wide shipping.