Tune Up Kit Delco EST 4 Cylinder | Sierra 18-5280
Tune Up Kit Delco EST 4 Cylinder | Sierra 18-5280
Sierra
46 in stock
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Tune Up Kit Delco EST 4 Cylinder | Sierra 18-5280
Tune Up Kit Delco EST 4 Cylinder | Sierra 18-5280
Keep your 4-cylinder marine engine running at peak performance with this essential tune-up kit. Featuring a replacement cap and rotor specifically engineered for Delco EST HEI module-in-cap distributors, this kit delivers the reliable ignition components your Sierra engine needs for smooth, consistent operation. Quick to install and built to last, it's the smart choice for preventative maintenance.
- For 4 cylinder Delco EST distributors
- Includes 18-5361 distributor cap and 18-5406 rotor
Additional Information
Maintaining your marine engine’s ignition system is critical for a smooth, reliable experience on the water. The Sierra 18-5280 Tune Up Kit is specifically engineered for 4-cylinder engines equipped with Delco EST (Electronic Spark Timing) ignitions. Whether you are dealing with a rough idle or performing routine seasonal maintenance, this kit provides the essential components to keep your vessel running at peak performance.
What’s Included in the Sierra 18-5280 Kit
This professional-grade tune-up kit is designed to replace worn-out ignition components that degrade over time due to heat, moisture, and electrical arc-over. The kit includes:
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18-5361 Distributor Cap: Features high-quality brass terminals for maximum conductivity and resistance to corrosion.
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18-5406 Rotor: Precision-molded to ensure an exact fit and consistent spark delivery to the distributor cap.
Compatibility and Interchangeable Parts
One of the primary benefits of the Sierra 18-5280 is its wide compatibility across various marine engine brands. It is a direct replacement for several OEM and aftermarket part numbers, including:
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Mercruiser: 811635Q2, 811635T2
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OMC: 986643 (Cap) and 986651 (Rotor)
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GLM: 71830
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Mallory: 9-29320
This kit is designed for In-Line 4 Delco EST systems, commonly found on Mercruiser, OMC, Crusader, Indmar, and Yamaha sterndrive or inboard motors.
Why Choose Sierra Marine Ignition Parts
Sierra is a leader in the marine aftermarket industry, known for producing parts that meet or exceed original equipment specifications. Using a high-quality tune-up kit like the 18-5280 offers several advantages:
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Improved Engine Starting: Fresh contacts ensure a strong spark, reducing cranking time.
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Enhanced Fuel Efficiency: Proper ignition timing and spark delivery help the engine burn fuel more completely.
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Corrosion Resistance: Marine environments are harsh. Sierra components are built with materials that resist the "green" corrosion often found on standard automotive parts.
Installation Tips for the Delco EST System
Replacing the cap and rotor is a straightforward DIY task for most boat owners. Before starting, ensure the battery is disconnected. When removing the old distributor cap, it is helpful to transfer the spark plug wires one by one to the new cap to maintain the correct firing order. Because the Delco EST system relies on precise electronic timing, ensuring these mechanical contact points are clean and new is the easiest way to prevent "misfires" and power loss during acceleration.
Optimize Your Boat's Performance Today
Don't wait for a breakdown in the middle of the lake to service your ignition system. Regular maintenance with the Sierra 18-5280 Tune Up Kit ensures your 4-cylinder Delco EST engine remains dependable season after season. By investing in premium components, you protect your engine from the long-term damage caused by poor combustion and ignition failure.
- Replaces Mercruiser 811635Q2
- Replaces Mallory 9-29320

! Compatibility references are provided for informational purposes only and do not constitute a fitment guarantee. Part numbers, application listings, and "replaces" cross-references are based on manufacturer data and are intended as a starting point for identification — not a guarantee of fit for your specific engine, hull, or installation.
Buyer is solely responsible for verifying compatibility with their engine model, serial number, model year, and trim configuration before purchase. If you are unsure whether this part fits your application, contact MacombMarineParts.com before you buy — we're available via text, email, or online chat to help verify compatibility for your specific application.
MacombMarineParts.com is not liable for parts ordered based on assumed fitment. Returns due to buyer-selected incorrect fitment are subject to our standard return and restocking fee policies.