Sierra 18-8800-1 Spark Plug Wire Set, MerCruiser 110/120/140 I/O, Replaces Mercury 84-813720A5, White

The Sierra 18-8800-1 is a white spark plug wire set built for MerCruiser inboard/outboard engines equipped with a contact-controlled distributor running standard rotation. This set is designed for the MerCruiser 110 and 120 (153 cid L4) and the MerCruiser 140 (181 cid L4), covering engines with the specific serial number ranges tied to those model years. It is not intended for MerCruiser engines equipped with Thunderbolt ignition systems.

Each set carries 4 wires to match the 4-cylinder MerCruiser engines it is built for, delivering a reliable connection between the distributor and spark plugs for consistent ignition performance. The wires are rated for 12 volts DC, standard for marine ignition systems of this type. As a direct cross-reference to Mercury Marine, OMC, and Mallory OEM numbers, this set is a straightforward replacement when factory ignition wiring wears out or fails on a covered MerCruiser engine.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-8800-1
• Color: White
• Number of Pins: 4
• Maximum Voltage: 12 Volts (DC)
• Weight: 0.77 pounds
• UPC: 808282194307
• Ignition Type: Contact-controlled distributor, standard rotation, excludes Thunderbolt ignition
• OEM Cross-Reference: Mercury Marine 84-813720A5, 84-816761Q4; OMC 503748; Mallory 9-28020
• Fitment: MerCruiser 110, 120, 140 I/O (153/181 cid L4)

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)

• Mercury Marine 84-813720A5
• Mercury Marine 84-816761Q4
• OMC 503748
• Mallory 9-28020

Frequently Asked Questions

What engines does the Sierra 18-8800-1 wire set fit? The 18-8800-1 fits MerCruiser 110 and 120 engines (153 cid L4) and the MerCruiser 140 (181 cid L4), each equipped with a contact-controlled distributor running standard rotation.

Will this wire set work on a MerCruiser with Thunderbolt ignition? No. The 18-8800-1 excludes MerCruiser engines with Thunderbolt ignition systems; it is built for contact-controlled distributor setups only.

What OEM part numbers does 18-8800-1 cross-reference? It cross-references Mercury Marine 84-813720A5 and 84-816761Q4, OMC 503748, and Mallory 9-28020.

How many wires come in the set? 4 wires, matching the 4-cylinder MerCruiser 110, 120, and 140 engines this set is designed for.

What color are the spark plug wires? The Sierra 18-8800-1 set is white.

What is the shipping weight of this part? The 18-8800-1 wire set weighs 0.77 pounds.

What years does the 18-8800-1 cover? Coverage is 1963-1966 for the MerCruiser 110, 1964-1986 for the MerCruiser 120, and 1968-1986 for the MerCruiser 140.

What voltage is the 18-8800-1 rated for? It is rated for 12 volts DC, standard for marine ignition wiring.

Is the 18-8800-1 an OEM or aftermarket part? It is a Sierra-manufactured replacement that cross-references directly to Mercury Marine, OMC, and Mallory OEM wire sets.

What is the UPC for this part? The Sierra 18-8800-1 carries UPC 808282194307.

Is there a difference in fitment between the 110/120 and the 140? Yes. The MerCruiser 110 and 120 use a 153 cid L4 engine, while the MerCruiser 140 uses a 181 cid L4 engine; both are covered by the 18-8800-1 set.