Free Ground Shipping to Continental US on
Piranha Propellers,
Propulsion & Performance Kits!
Keep Your Crusader Engine Running Strong with Genuine or OEM-Grade Parts from...
$0.00 USD
Minimum Order of $20 Required for Checkout
Sierra
98 in stock
Couldn't load pickup availability
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.
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.
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:
18-5361 Distributor Cap: Features high-quality brass terminals for maximum conductivity and resistance to corrosion.
18-5406 Rotor: Precision-molded to ensure an exact fit and consistent spark delivery to the distributor cap.
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:
Mercruiser: 811635Q2, 811635T2
OMC: 986643 (Cap) and 986651 (Rotor)
GLM: 71830
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.
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:
Improved Engine Starting: Fresh contacts ensure a strong spark, reducing cranking time.
Enhanced Fuel Efficiency: Proper ignition timing and spark delivery help the engine burn fuel more completely.
Corrosion Resistance: Marine environments are harsh. Sierra components are built with materials that resist the "green" corrosion often found on standard automotive parts.
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.
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.

Would have been 5 stars but, I did not receive a promotional sticker with my $2000 drive unit. Just kidding, everything was great!
Great company to work with!
Ordered a Piranha Propellers Complete A-Series 4 Blade Propeller from Macomb Marine Parts and even though we’re international, it arrived in just over a week — fast and reliable service. The propeller itself is a real lifesaver. We had the same model before, and after hitting a rock that damaged two blades, we were able to swap them right on the water and make it back to the marina without issue — something you simply can’t do with a regular aluminum prop. For peace of mind we decided to buy a complete new set (hub and blades) since an impact like that could cause hidden damage, but the system really proved its worth.
3 in. Exhaust Elbow | Pleasurecraft R029001
Excellent part.
I couldn’t find a Piranha propeller dealer near me in Canada but found Macomb Marine Parts who could deliver to me. The order process was smooth and I was even contacted via email for clarification regarding blade shape and they were very helpful in choosing the best shape for my purposes.
I can’t comment on the prop’s performance yet as we haven’t had the boat in the water yet.
Perfect replacement. thank you
Perfect replacement
Perfect match to the original Chris Craft blue. Competitive price and delivery was quick
Great Product, easy to install, work well
Obtaining magnesium anodes to install on the OMC Cobra (SX-C) sterndrive, for fresh water use. Received the anode within a week of ordering the part, which is not going to be installed until Spring.
Black Liquid Electrical Tape - 4 oz. | Star Brite 084104B
As described
Very Happy!! Just what I needed!!
Outdrive spent 4 months docked in salt water with no visible rust on the stainless steel braided hoses
Would have been 5 stars but, I did not receive a promotional sticker with my $2000 drive unit. Just kidding, everything was great!
Great company to work with!
Ordered a Piranha Propellers Complete A-Series 4 Blade Propeller from Macomb Marine Parts and even though we’re international, it arrived in just over a week — fast and reliable service. The propeller itself is a real lifesaver. We had the same model before, and after hitting a rock that damaged two blades, we were able to swap them right on the water and make it back to the marina without issue — something you simply can’t do with a regular aluminum prop. For peace of mind we decided to buy a complete new set (hub and blades) since an impact like that could cause hidden damage, but the system really proved its worth.
Fill in the required details to get notified when the product is again in stock!
Thanks, We Will Notify You When Product Back In Stock!!