Sierra 18-5281 Tune-Up Kit - GM V-8 Distributor Cap and Rotor, Fits 1996-2005 Indmar Monsoon, MCX, RPT, Hammerhead

The Sierra 18-5281 Tune-Up Kit is a distributor cap and rotor set built as a direct replacement for GM V-8 Delco EST marine ignition systems. The kit contains a Sierra 18-5354 distributor cap and an 18-5405 rotor, giving boat owners the two most common ignition wear parts in a single package for a routine tune-up or ignition service. Replacing the cap and rotor together helps restore reliable spark delivery, smoother idle, and consistent starting on engines where these components have worn, cracked, or corroded from heat cycling and moisture exposure typical of a marine engine compartment.

Kit 18-5281 is interchangeable with GLM 71810, Mallory 9-29308, and Mercruiser 808483Q2, so it can be cross-referenced against those part numbers when sourcing a replacement. It fits 1996-2005 Indmar Monsoon, MCX, RPT, and Hammerhead engines.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-5281
• Included Components: Distributor cap (18-5354), rotor (18-5405)
• Engine Compatibility: GM V-8 Delco EST ignition
• Color: Multi-colored
• Weight: 0.61 pounds
• UPC: 808282105105

Fitment

• 1996-2005 Indmar Monsoon, MCX, RPT, and Hammerhead engines

Replaces (OEM)

• GLM 71810
• Mallory 9-29308
• Mercruiser 808483Q2

Frequently Asked Questions

What is included in the Sierra 18-5281 Tune-Up Kit? The kit contains a Sierra 18-5354 distributor cap and an 18-5405 rotor, the two parts needed for a distributor cap and rotor tune-up on covered GM V-8 marine ignition systems.

What engines does the 18-5281 Tune-Up Kit fit? It fits 1996-2005 Indmar Monsoon, MCX, RPT, and Hammerhead engines equipped with a GM V-8 Delco EST ignition system.

Is the 18-5281 kit interchangeable with other brands' part numbers? Yes, Sierra 18-5281 is interchangeable with GLM 71810, Mallory 9-29308, and Mercruiser 808483Q2.

Does the 18-5281 kit include spark plugs or plug wires? No, the kit is limited to the distributor cap (18-5354) and rotor (18-5405); it does not include spark plugs or ignition wires.

How much does the Sierra 18-5281 Tune-Up Kit weigh? The complete kit weighs 0.61 pounds.

What is the UPC for the Sierra 18-5281 Tune-Up Kit? The UPC for Sierra Tune-Up Kit 18-5281 is 808282105105.

Can I order just the cap or just the rotor separately? The 18-5281 listing is sold as a combined kit containing both the 18-5354 cap and 18-5405 rotor rather than as individual components.

Will the 18-5281 kit work on any GM V-8 marine engine? It is built for GM V-8 Delco EST ignition systems and is confirmed to fit 1996-2005 Indmar Monsoon, MCX, RPT, and Hammerhead engines; compatibility outside those applications should be checked against your engine's existing distributor cap and rotor part numbers.

Why replace the distributor cap and rotor together? Cap and rotor wear at a similar rate from heat and electrical arcing, so the Sierra 18-5281 kit pairs both parts to restore consistent spark timing and avoid mismatched wear between old and new components.

Is Sierra 18-5281 a genuine Sierra part? Yes, 18-5281 is a Sierra-branded Tune-Up Kit manufactured under the Sierra part number 18-5281.