Sierra 18-5834 Starter Solenoid, Replaces Mercury 89-817109A2, for 100 HP and 105 Jet 4 Cyl Outboards

The Sierra 18-5834 Starter Solenoid is a direct-fit replacement solenoid engineered to meet or exceed original equipment quality for Mercury 100 HP and 105 Jet 4-cylinder outboard engines. The solenoid switches the high-amperage starter circuit when the ignition key is engaged, using a low-current signal from the ignition switch to close the internal contacts and send full battery power to the starter motor. It is built with a metal housing finished in black and is designed for wall mounting in the engine compartment, matching the physical footprint and terminal layout of the original Mercury unit it replaces.

This solenoid is application-specific to the fitment listed below, including engines fitted with a 5/16-18 inch starter terminal and either 1 Ram Trim or 3 Ram Trim configurations. Because Sierra manufactures this part to original equipment specifications, it installs using the factory mounting points and wiring without modification. Boat owners and marine technicians use the 18-5834 as a like-for-like swap when an original Mercury starter solenoid fails or shows signs of a weak or intermittent starter engagement.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-5834
• Product Type: Starter Solenoid
• Material: Metal
• Color: Black
• Mounting Type: Wall Mount
• Dimensions: 4.2 x 2.9 x 2.5 inches
• Weight: 0.76 pounds
• UPC: 808282105990
• OEM Cross Reference: Arco SW109, GLM 72500, Mallory 9-15117, Mercury 89-817109A2, 89-817109A1, Mercury Sport Jet 817109A2

Fitment

• Mercury 100 HP 4 Cyl. With 1 Ram Trim and 5/16-18 inch starter terminal
• Mercury 100 HP 4 Cyl. With 3 Ram Trim and 5/16-18 inch starter terminal
• Mercury 100 HP 4 Cyl.
• Mercury 100 HP 4 Cyl. (later production)
• Mercury 105 Jet with rubber mounted starter solenoid

Replaces (OEM)

• Arco SW109
• GLM 72500
• Mallory 9-15117
• Mercury 89-817109A2
• Mercury 89-817109A1
• Mercury Sport Jet 817109A2

Frequently Asked Questions

What engines does the Sierra 18-5834 starter solenoid fit? The Sierra 18-5834 fits Mercury 100 HP 4-cylinder outboards, including versions with 1 Ram Trim or 3 Ram Trim and a 5/16-18 inch starter terminal, as well as Mercury 105 Jet outboards equipped with a rubber mounted starter solenoid.

Is the Sierra 18-5834 an OEM part or aftermarket? It is an aftermarket solenoid manufactured by Sierra to meet or exceed the quality of the original equipment part it replaces, rather than a Mercury-branded OEM component.

What OEM part numbers does the Sierra 18-5834 solenoid cross with? It is interchangeable with Arco SW109, GLM 72500, Mallory 9-15117, Mercury 89-817109A2, Mercury 89-817109A1, and Mercury Sport Jet 817109A2.

What are the dimensions of the 18-5834 solenoid? The Sierra 18-5834 measures 4.2 x 2.9 x 2.5 inches.

How much does the 18-5834 starter solenoid weigh? This solenoid weighs 0.76 pounds.

What material is the Sierra 18-5834 solenoid made from? The housing is made of metal, finished in black.

How is the Sierra 18-5834 solenoid mounted? It uses a wall mount design, matching the mounting configuration of the original starter solenoid it replaces.

Does this solenoid fit engines with 3 Ram Trim? Yes, the 18-5834 fits Mercury 100 HP 4-cylinder engines with 3 Ram Trim and a 5/16-18 inch starter terminal, as well as the 1 Ram Trim version.

Will the 18-5834 work on a 105 Jet outboard? Mercury 105 Jet outboards equipped with a rubber mounted starter solenoid use the Sierra 18-5834; models with a flush mounted starter solenoid require a different Sierra part.

What is included when I order the 18-5834? The order includes one Sierra 18-5834 starter solenoid; no additional hardware or wiring is included.

Does the 5/16-18 starter terminal size matter for fitment? Yes, the Sierra 18-5834 is designated for engines with a 5/16-18 inch starter terminal, so confirming this terminal size on your engine helps ensure correct fitment.