Sierra 18-99430 Distributor Trigger Housing, Replaces 393-3736 - Fits Mercury Mariner 80-150 HP 4/6 Cylinder Outboards

The Sierra 18-99430 is a distributor trigger housing built for Mercury and Mariner outboard motors equipped with battery powered distributors. This housing is a wear item in the ignition triggering system, and a cracked, worn, or failed unit can cause misfires, hard starting, or a no-spark condition. Replacing it with the Sierra 18-99430 restores proper distributor timing signal generation so the ignition system fires correctly across the RPM range.

It is designed to fit Mercury/Mariner 80 and 85 HP 4 cylinder outboards and 90, 110, 115, 135, 140, and 150 HP 6 cylinder outboards that use a battery powered distributor setup. The housing is a direct cross-reference for multiple Mercury OEM part numbers, making it a straightforward like-for-like replacement for the factory unit. It mounts to the engine as part of the distributor assembly and is finished for durability in a marine engine bay environment.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-99430
• Weight: 1.6 pounds
• Color: Multicolored
• Engine Type: Marine
• Mounting Type: Engine Mount
• Fuel Type: Gasoline
• Maximum Horsepower: 150 Horsepower
• Recommended Use: Repair or replacement of Mercury/Mariner outboard motor distributor trigger housings
• OEM Cross-Reference: 332-4177, 332-4177A 3, 393-3736A79, 393-3736, 393-3736A 3, 393-3736A23, 393-3736A77

Fitment

• Mercury/Mariner 80 and 85 HP (4 cylinder), 1969-1975, with battery powered distributor
• Mercury/Mariner 90, 110, 115, 135, 140, and 150 HP (6 cylinder), 1967-1979, with battery powered distributor

Replaces (OEM)

• 332-4177
• 332-4177A 3
• 393-3736A79
• 393-3736
• 393-3736A 3
• 393-3736A23
• 393-3736A77

Frequently Asked Questions

What engines does the Sierra 18-99430 distributor trigger housing fit? It fits Mercury/Mariner 80 and 85 HP 4 cylinder outboards from 1969-1975, and Mercury/Mariner 90, 110, 115, 135, 140, and 150 HP 6 cylinder outboards from 1967-1979, specifically those equipped with a battery powered distributor.

Which OEM part numbers does the 18-99430 replace? The Sierra 18-99430 cross-references to Mercury OEM numbers 332-4177, 332-4177A 3, 393-3736A79, 393-3736, 393-3736A 3, 393-3736A23, and 393-3736A77.

Is this the correct part for a non-battery powered distributor? No. The Sierra 18-99430 is designed specifically for Mercury/Mariner engines with a battery powered distributor, so confirm your distributor type before ordering.

How much does the 18-99430 trigger housing weigh? The Sierra 18-99430 distributor trigger housing weighs 1.6 pounds.

What color is the housing? The Sierra 18-99430 is finished in a multicolored appearance as supplied.

Will the 18-99430 work on both 4 cylinder and 6 cylinder Mercury outboards? Yes, one housing covers both the 80/85 HP 4 cylinder range and the 90-150 HP 6 cylinder range, as long as the engine uses a battery powered distributor.

Is the 18-99430 a genuine Mercury part or an aftermarket replacement? It is a Sierra branded replacement part, not a Mercury branded original, but it is built to match the fit and function of the OEM housing it cross-references.

What symptoms indicate the trigger housing needs replacement? Misfires, hard starting, or a no-spark condition on a Mercury/Mariner outboard with a battery powered distributor can point to a worn or failed distributor trigger housing like the 18-99430.

Does the 18-99430 include mounting hardware or a full distributor? The Sierra 18-99430 is the distributor trigger housing component itself; check your engine's assembly to confirm what additional hardware or components you already have.

Can I use the 18-99430 as a direct swap for my old housing without other modifications? Since the 18-99430 cross-references the original Mercury housing numbers for your engine, it is intended as a direct fit replacement on the applicable 80-150 HP battery powered distributor engines.