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Sierra 18-99309 Ignition Condenser for Mercury Mariner Outboard Engines

Manufacturer

Sierra

<h3>Sierra: Six Decades of Marine Aftermarket Excellence</h3><p><strong>Sierra</strong> has spent nearly 60 years earning its reputation as one of the most trusted names in the marine aftermarket industry. Originally focused on engine and drive components for boats, the brand has grown into a comprehensive source for nearly everything a boater needs to keep their vessel running at its best — from precision instrumentation to complete engine rebuild hardware.</p><p>Now operating as a brand of Dometic, Sierra manages global aftermarket distribution from a 300,000 sq. ft. facility in Litchfield, Illinois. The Sierra brand today encompasses not only its flagship marine parts line but also well-established marine names like Shields and Moeller, offering boaters a broader catalog than ever before. Whether you own an outboard, inboard, or sterndrive, Sierra's engineering team designs products to meet or exceed OEM specifications.</p><h3>Precision Instrumentation You Can Trust on the Water</h3><p>One of Sierra's most recognized product areas is its marine instrumentation lineup. The brand's <a href="/7570-sierra-gauge-set-1480">gauge sets</a> cover everything from classic analog instrument clusters to advanced digital multi-function displays. Sierra offers packages suited to outboards, sterndrives, and gasoline-powered inboards, with options ranging from coordinated analog kits in styles like Arctic, Eclipse, and Amega to modern touchscreen solutions like the R3 multi-function gauge. Features such as scratch-resistant domed glass lenses, silicone-dampened pointers, and perimeter backlighting make these instruments highly readable in all conditions.</p><p>Behind every accurate gauge reading is a properly calibrated sending circuit. Sierra's <a href="/7570-sierra-gauge-resistor-47908">gauge resistors</a> are a critical part of that chain, ensuring the signals from sensors and sending units are correctly interpreted by your instruments. These components are built to marine-grade standards to resist moisture, vibration, and corrosion — the realities of life on the water.</p><h3>Engine Internals Built to OEM Standards</h3><p>Sierra's history in marine power is perhaps best demonstrated by its deep catalog of engine components. The brand's <a href="/7570-sierra-engine-gasket-set-5404">engine gasket sets</a> cover a wide range of outboard and inboard applications and are engineered to deliver reliable seals in the demanding thermal and chemical environment of a marine engine. For boaters performing seasonal overhauls, top-end rebuilds, or full engine restorations, Sierra gasket kits are a go-to resource trusted by professional marine technicians and DIY boaters alike.</p><h3>A Complete Marine Parts Partner</h3><p>Beyond instrumentation and engine internals, Sierra's catalog spans fuel systems, electrical supplies, steering components, shore power, and more — all covered by what the brand calls an industry-leading warranty. Sierra also maintains a comprehensive parts-finder tool that enables cross-referencing with OEM part numbers from major manufacturers including Mercury, Yamaha, Suzuki, Volvo Penta, and others, making it straightforward to find the right replacement part for virtually any application.</p>

Part Number

118-99309
09/11/2036 10:46 PM
Sale Price

$47.40

1 left at this price

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Product Details

The Sierra 18-99309 is a replacement ignition condenser designed for Mercury and Mariner outboard engines equipped with the red module ignition system. This essential ignition component ensures reliable spark delivery and proper engine timing for smooth operation.

Key Features:

  • Designed for Mercury/Mariner 4 HP, 4.5 HP, 7.5 HP, 9.8 HP, and 20 HP outboard engines
  • Compatible with red module ignition systems on 1972-1989 models
  • Replaces Mercury OEM part numbers 336-4463 and CDI 994-4463
  • Marine-grade construction built to withstand harsh saltwater environments
  • Meets or exceeds original equipment specifications

This condenser is a critical component of the breaker point ignition system, storing and releasing electrical energy to create a strong spark at the spark plug. Regular replacement during tune-ups helps maintain optimal engine performance and prevents misfires.

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It was good

I'm very satisfied with my purchase for the 2nd time. I will be making more purchases in a few months.

It was good

Great service, only hiccup was I paid for 2 day shipping $9.99 Item took 5 days. I was credited the $9.99 No big deal, will order from boatplicity.com again!

Very quick service - great products!! Highly recommend!

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