Sierra 18-5186 Ignition Coil for Mercury/Mariner and Chrysler/Force Outboard Engines

The Sierra 18-5186 is an ignition coil built for select Mercury/Mariner and Chrysler/Force outboard engines, supplying the coil-near-plug spark energy needed to fire the spark plugs at the correct interval. It ships one coil per package and is intended as a direct replacement for the original equipment coil on covered engines, with Sierra stating that each unit meets or exceeds the performance of the original part it replaces. The coil uses a female connector for a secure plug-in fit to the existing wiring harness, and its compact 0.39 x 0.39 x 0.39 inch body allows it to mount in the same location as the factory unit without modification.

Fitment is engine-serial-number specific across a range of Mercury/Mariner outboard horsepower ratings, including 15 hp, 15XD, 18 hp, and 20 hp models, spanning Sea-Pro, Commercial, Non-Commercial, and BULLET Commercial variants, so buyers should confirm their engine's serial number falls within the covered range before ordering. This is a fit-specific ignition part, so checking part numbers against the original coil is recommended to ensure proper fit.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-5186
• Product Type: Ignition Coil
• Connector Gender: Female
• Installation Type: Coil-near-plug
• Item Dimensions: 0.39 x 0.39 x 0.39 inches
• Weight: 0.41 pounds
• Unit Count: 1 coil per package
• UPC: 030999236814
• Compatible Engines: Select Mercury/Mariner and Chrysler/Force outboard engines

Fitment

• Mercury/Mariner 15 hp, serial number B292414-G760299 and later ranges through G760300 & up
• Mercury/Mariner 15 hp Sea-Pro, serial number G044027-G437999
• Mercury/Mariner 15 hp Commercial and Non-Commercial, serial number G760300 & up
• Mercury/Mariner 15XD Commercial and Non-Commercial, serial number G760300 & up (Non-Commercial from 760300 & up)
• Mercury/Mariner 18 hp, serial number 5837437-6443972 and 6443973 & up
• Mercury/Mariner 18 hp BULLET Commercial, serial number 6443973 & up
• Mercury/Mariner 20 hp, serial number 3537531-3755884, 6443973-G044026, G044027-G437999, and G438000-G760299
• Mercury/Mariner 20 hp Commercial and Non-Commercial, serial number G760300-T800999

Replaces (OEM)

• Mallory 9-23200
• Chrysler/Force/US Marine 339-7370A23
• Chrysler/Force F718475
• Mercury Sport Jet 339-832757A4
• Mercury Race Outboard 339-7370A13
• Mercury Marine 338-4774A1
• Mercury Marine 338-4995A1
• Mercury Marine 338-4995A2
• Mercury Marine 339-7370A16
• Mercury Marine 339-7370A17
• Mercury Marine 339-7370A19
• Mercury Marine 339-7370A2
• Mercury Marine 339-7370A6
• Mercury Marine 339-7370A8
• Mercury Marine 339-7370B13
• Mercury Marine 339-832757A3
• Mercury Marine 339-832757B4

Frequently Asked Questions

What engines does the Sierra 18-5186 ignition coil fit? The Sierra 18-5186 fits select Mercury/Mariner outboard engines in the 15 hp, 15XD, 18 hp, and 20 hp range, including Sea-Pro, Commercial, Non-Commercial, and BULLET Commercial variants, as well as select Chrysler/Force outboard engines. Because coverage is tied to engine serial number, confirm your engine's serial number falls within the listed range before ordering part 18-5186.

How many ignition coils come in the package? One Sierra 18-5186 ignition coil is included per package.

Is the 18-5186 coil an OEM part or aftermarket? The 18-5186 is a Sierra-branded replacement coil, not an original Mercury or Chrysler/Force part, but Sierra states it meets or exceeds the performance of the original equipment coil it replaces.

What OEM part numbers does the 18-5186 replace? The 18-5186 is interchangeable with Mallory 9-23200; Chrysler/Force/US Marine 339-7370A23 and F718475; Mercury Sport Jet 339-832757A4; Mercury Race Outboard 339-7370A13; and Mercury Marine numbers 338-4774A1, 338-4995A1, 338-4995A2, 339-7370A16, 339-7370A17, 339-7370A19, 339-7370A2, 339-7370A6, 339-7370A8, 339-7370B13, 339-832757A3, and 339-832757B4.

What is the connector type on this ignition coil? The Sierra 18-5186 uses a female connector for a plug-in fit to the engine's existing ignition wiring.

What are the dimensions of the 18-5186 ignition coil? The coil measures 0.39 x 0.39 x 0.39 inches and weighs 0.41 pounds.

Does the 18-5186 coil work on a 20 hp Mercury outboard? Yes, part 18-5186 covers Mercury/Mariner 20 hp outboards across several serial number ranges, including 3537531-3755884, 6443973-G044026, G044027-G437999, G438000-G760299, and G760300-T800999 for Commercial and Non-Commercial models. Check your engine's serial number against these ranges to confirm coverage.

Will this coil fit an 18 hp BULLET Commercial engine? Part number 18-5186 is listed for the 18 hp BULLET Commercial engine with serial number 6443973 and up.

How is the ignition coil installed? The Sierra 18-5186 is designed as a direct replacement for the original coil, connecting via its female connector in the same mounting location as the factory unit, though a qualified marine technician should perform the swap to ensure correct timing and connections.

Is the 18-5186 fit specific or a universal coil? The 18-5186 is fit specific to particular Mercury/Mariner and Chrysler/Force outboard engine models and serial number ranges, so part numbers should be checked against the original coil before purchase.

What is the UPC for the Sierra 18-5186 ignition coil? The UPC for the Sierra 18-5186 ignition coil is 030999236814.