Sierra Power Pack 18-5794-1 for Johnson/Evinrude 20, 25, 28 HP Outboards 1989-92

The Sierra 18-5794-1 Power Pack is an ignition control module built as a direct replacement for Johnson/Evinrude outboard engines. It replaces the factory power pack that regulates ignition timing and spark delivery for the engine, and is a common failure point that causes hard starting, misfiring, stalling, or a complete no-spark condition on affected outboards. Installing a new power pack restores factory ignition timing control without the guesswork of troubleshooting an aging original unit.

This unit is designated for Johnson/Evinrude outboards in the 20 HP, 25 HP, and 28 HP range for the 1989-92 model years. Confirm your outboard's horsepower rating and model year against the fitment list below before ordering, since Johnson/Evinrude power packs are year- and horsepower-specific and an incorrect match will not function correctly.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-5794-1
• Product Type: Power Pack
• UPC: 808282374792
• Compatible Outboard Horsepower: 20 HP, 25 HP, 28 HP
• Compatible Model Years: 1989-92
• Weight: 0.79 pounds
• Product Dimensions: 2.38 x 6.38 x 2.44 inches
• Category: Evinrude Outboard Power Packs

Fitment

• Johnson/Evinrude 20 HP, 1989-92
• Johnson/Evinrude 25 HP, 1989-92
• Johnson/Evinrude 28 HP, 1989-92

Frequently Asked Questions

What does the Sierra 18-5794-1 power pack fit? The Sierra 18-5794-1 fits Johnson/Evinrude outboards rated at 20 HP, 25 HP, and 28 HP for the 1989-92 model years. Check your outboard's horsepower and model year before ordering, since Johnson/Evinrude power packs are matched to a specific year range.

Will this power pack work on a 1993 or newer Johnson/Evinrude outboard? No, the 18-5794-1 power pack is matched to the 1989-92 model years for the 20, 25, and 28 HP Johnson/Evinrude outboards; a different Sierra part number applies to 1993 and later model years.

What does a power pack actually do on an outboard motor? A power pack, also called an ignition module, controls the ignition timing and spark delivery to the engine's cylinders. The Sierra 18-5794-1 replaces this component on covered Johnson/Evinrude outboards when the factory unit fails or degrades.

What are the symptoms of a failing power pack? Hard starting, engine misfire, random stalling, rough idle, or a complete loss of spark are common signs that the ignition power pack needs replacement on a Johnson/Evinrude outboard. The 18-5794-1 is designed to restore normal ignition function on the outboards it is matched to.

Is the Sierra 18-5794-1 an OEM part or aftermarket replacement? The 18-5794-1 is a Sierra-brand replacement power pack designed to restore ignition function on the specific Johnson/Evinrude outboards it is matched to, rather than a part sourced directly from Johnson/Evinrude.

How much does the 18-5794-1 power pack weigh? The Sierra 18-5794-1 power pack weighs 0.79 pounds.

What are the dimensions of this power pack? The Sierra 18-5794-1 measures 2.38 x 6.38 x 2.44 inches.

Does the 18-5794-1 fit both 25 HP recreational and 25 HP commercial Johnson/Evinrude outboards? The 18-5794-1 covers the 25 HP Johnson/Evinrude outboards for the 1989-92 model years; commercial 25 HP variants from other year ranges use a different Sierra power pack number, so confirm the model year on your outboard before ordering.

Is installation of the 18-5794-1 power pack straightforward? The Sierra 18-5794-1 is designed as a direct-fit replacement for the ignition power pack on covered Johnson/Evinrude outboards, mounting in the same location as the original unit using the factory wiring connections.

What horsepower outboards use the 18-5794-1 power pack? The 18-5794-1 is used on 20 HP, 25 HP, and 28 HP Johnson/Evinrude outboards built for the 1989-92 model years.