CDI Electronics 118-99311 Mercury Mariner 4 Cylinder Switch Box Kit, Replaces 337-4406

The CDI Electronics 118-99311 is an ignition switch box kit built for Mercury and Mariner outboard engines. It serves as the electronic control unit that manages spark timing and signal distribution to the powerhead, and is a direct replacement for the original equipment switch box on applicable engines. The kit is supplied complete so the installer does not need to source individual components separately: it includes the switch box assembly, a disk assembly compatible with both 4 and 6 cylinder configurations, a spacer, and bearings needed for a proper fit. This all-in-one packaging is intended to simplify replacement of a failed or aging switch box without requiring a parts hunt across multiple listings.

This switch box kit fits most Mercury and Mariner 4 and 6 cylinder outboard engines from 1967 to 1977. Because the kit ships with disks sized for both 4 and 6 cylinder engines, it covers either configuration from a single kit. It is designed as a functional and physical replacement for the original Mercury switch box, cross-referencing to several OEM Mercury part numbers used across that production span. The complete kit weighs 3.9 pounds as packaged.

Specifications

• Brand: CDI Electronics
• Manufacturer Part Number: 118-99311
• Product Type: Ignition Switch Box Kit
• Application: Mercury / Mariner Outboard Engines
• Compatible Cylinders: 4 & 6 Cylinder Engines
• Fitment Years: 1967-1977
• Kit Contents: Switch box assembly, disk assembly (4/6 cylinder), spacer, bearings
• OEM Cross Reference: Mercury 337-4406, 337-4411, 393-3736A78
• Weight: 3.9 pounds
• UPC: 736983850553

Fitment

• Most Mercury / Mariner 4 & 6 Cylinder Outboard Engines, 1967-1977

Replaces (OEM)

• Mercury 337-4406
• Mercury 337-4411
• Mercury 393-3736A78

Frequently Asked Questions

What engines does the CDI Electronics 118-99311 switch box kit fit? The 118-99311 kit fits most Mercury and Mariner 4 and 6 cylinder outboard engines built from 1967 to 1977.

Does this kit work on both 4 cylinder and 6 cylinder Mercury outboards? Yes, the CDI 118-99311 kit ships with disks sized for both 4 and 6 cylinder engines, so a single kit covers either configuration.

What OEM Mercury part numbers does the 118-99311 replace? It replaces Mercury OEM numbers 337-4406, 337-4411, and 393-3736A78.

What comes included in the switch box kit? The 118-99311 kit includes the switch box assembly, a 4/6 cylinder disk assembly, a spacer, and bearings needed for installation.

How much does the CDI 118-99311 switch box kit weigh? The complete kit weighs 3.9 pounds.

Is the CDI 118-99311 a genuine replacement or an aftermarket equivalent? The 118-99311 is a CDI Electronics switch box kit engineered as a direct functional replacement for the original Mercury switch box on applicable 1967-1977 4 and 6 cylinder outboards, cross-referenced to the OEM Mercury numbers it replaces.

Do I need any additional parts to install this switch box kit? No additional hardware should be needed since the 118-99311 kit already includes the switch box, disk assembly, spacer, and bearings required for the swap.

Will this switch box kit fit a Mariner-branded outboard as well as a Mercury? Yes, the 118-99311 is designed for both Mercury and Mariner 4 and 6 cylinder outboard engines within the 1967-1977 fitment range.

What is the UPC for the CDI 118-99311 switch box kit? The UPC for this kit is 736983850553.

Can this kit be used on an outboard newer than 1977? The 118-99311 kit's stated fitment covers most Mercury/Mariner 4 and 6 cylinder engines from 1967 to 1977; fitment outside that range is not specified.