Sierra 18-5385 Distributor Cap, Replaces Mercruiser 393-9459Q1, Fits MerCruiser 110/120/140 4-Cyl I/O

The Sierra 18-5385 Distributor Cap is a direct-fit ignition component for MerCruiser 4-cylinder sterndrive engines using a contact-controlled, standard-rotation distributor. It is molded from durable plastic with a machined white finish and a twist-on closure that seats securely over the distributor housing for a reliable weatherproof connection to the ignition system.

This cap is engineered for MerCruiser 110, 120, and 140 model engines equipped with Delco conventional ignition, and it is not intended for use on Thunderbolt ignition systems. It cross-references to a range of OEM and aftermarket part numbers used across Mercruiser, Chris-Craft, GLM, Evinrude/Johnson, and Mallory catalogs, making it a convenient way to source a replacement cap regardless of which brand's part number you started with. Each Sierra distributor cap is built to meet or exceed the fit, form, and function of the original equipment part it replaces.

The 18-5385 cap is the distributor cap component of a broader MerCruiser tune-up lineup that also includes a matching contact set, rotor, coil, distributor, and spark plug wires, so it can be ordered on its own for a cap-only replacement or alongside those companion parts for a full ignition service.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-5385
• Product Type: Distributor Cap
• Material: Plastic
• Color: White
• Exterior Finish: Machined
• Closure Type: Twist-On
• Item Dimensions: 0.39 x 0.39 x 0.39 inches
• Weight: 0.47 pounds
• Ignition System Type: Contact-controlled, standard rotation, Delco conventional ignition (excludes Thunderbolt ignition)
• Fitment: MerCruiser 110, 120, 140 4-cylinder I/O engines

Fitment

• MerCruiser 110 (153 cid L4), 1963-1966, Serial Number 1537370-2044033
• MerCruiser 120 (153 cid L4), 1964-1986, Serial Number 1666601-B531853
• MerCruiser 140 (181 cid L4), 1968-1986, Serial Number 2508261-B450800

Replaces (OEM)

• 16.69-00052
• 71540
• 380541
• 9-29401
• 393-9459Q1
• 393-9459
• 393-9549T
• 33667
• FI6900052

Frequently Asked Questions

What engines does the Sierra 18-5385 distributor cap fit? The 18-5385 fits MerCruiser 110 (1963-1966), MerCruiser 120 (1964-1986), and MerCruiser 140 (1968-1986) 4-cylinder I/O engines running Delco conventional ignition.

Will this cap work on a Thunderbolt ignition system? No. The 18-5385 is designed for contact-controlled, standard-rotation distributors and specifically excludes Thunderbolt ignition setups.

Is the 18-5385 a genuine Sierra part or an aftermarket replacement? It is a Sierra-manufactured aftermarket distributor cap engineered to meet or exceed the fit and performance of the original equipment part it replaces.

What OEM numbers does the Sierra 18-5385 cross to? It cross-references to Mercruiser 393-9459Q1, 393-9459, 393-9549T, 33667, and FI6900052, Chris-Craft 16.69-00052, GLM 71540, Evinrude/Johnson 380541, and Mallory 9-29401.

What is the distributor cap made of? The 18-5385 is molded from plastic with a machined white exterior finish.

How big is the 18-5385 distributor cap? It measures 0.39 x 0.39 x 0.39 inches and weighs 0.47 pounds.

How does the cap attach to the distributor? The 18-5385 uses a twist-on closure that secures directly over the distributor housing.

What comes in the box with the 18-5385? Each order includes one Sierra 18-5385 distributor cap only.

Do I need any other parts along with this cap for a tune-up? The 18-5385 is the cap component of a MerCruiser 4-cylinder ignition lineup that also includes a matching rotor, contact set, coil, distributor, and spark plug wires, which can be ordered separately if a full tune-up is needed.

Does the 18-5385 fit GM 4-cylinder engines outside of MerCruiser applications? Yes, it is built for GM 4-cylinder engines equipped with Delco conventional ignition, which includes the MerCruiser 110, 120, and 140 applications listed for this cap.

What's the difference between this cap and the OEM Mercruiser 393-9459Q1? The Sierra 18-5385 is a direct cross-reference to Mercruiser 393-9459Q1 and is built to match its fit and function as a replacement part.

Is the 18-5385 covered by a warranty? Yes, the Sierra 18-5385 distributor cap is covered under Sierra's standard limited warranty.