Sierra 18-99173 Power Pack, Replaces 763796, Fits Johnson/Evinrude 60/70/75 HP 3-Cylinder Outboards 1986-1990

The Sierra 18-99173 is a power pack for Johnson/Evinrude 3-cylinder outboard engines. It is the ignition control module that regulates spark timing and delivery across the cylinders, and it is a direct fit for 60, 70, and 75 HP Johnson/Evinrude outboards built between 1986 and 1990. A failing or worn power pack is a common cause of hard starting, misfiring, rough idle, or a no-spark condition on these engines, and replacing it with the correct 3-cylinder unit restores reliable ignition performance.

This power pack is sized to fit within the existing engine wiring harness and mounting points used on the applicable 1986-1990 Johnson/Evinrude 3-cylinder powerheads, with overall dimensions of 5.75 x 4.37 x 2.32 inches. It corresponds to the OEM power pack numbers 763796, 583125, 582115, and 583143, so it is intended as a like-for-like replacement for engines originally equipped with any of those units. Because engine manufacturers used multiple power pack revisions across production runs, buyers should confirm the OEM number currently on their engine against the replacement numbers listed here before ordering.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-99173
• Product Type: Power Pack
• Engine Make: Johnson/Evinrude
• Cylinders: 3
• Fits Horsepower: 60, 70, 75 HP
• Fits Years: 1986-1990
• Weight: 0.6 pounds
• Dimensions: 5.75 x 4.37 x 2.32 inches

Fitment

• Johnson/Evinrude 3-cylinder outboards, 60, 70, and 75 HP, 1986-1990

Replaces (OEM)

• 763796
• 583125
• 582115
• 583143

Frequently Asked Questions

What engines does the Sierra 18-99173 power pack fit? The Sierra 18-99173 fits Johnson/Evinrude 3-cylinder outboard engines rated at 60, 70, and 75 HP, built between 1986 and 1990.

Which OEM part numbers does 18-99173 replace? It replaces OEM power pack numbers 763796, 583125, 582115, and 583143 on applicable Johnson/Evinrude 3-cylinder outboards.

Is this a genuine Johnson/Evinrude part or an aftermarket replacement? The 18-99173 is sold under the Sierra part number as a replacement for the original Johnson/Evinrude power pack numbers 763796, 583125, 582115, and 583143, not an OEM-branded unit.

How much does the 18-99173 power pack weigh? It weighs 0.6 pounds.

What are the physical dimensions of this power pack? The unit measures 5.75 x 4.37 x 2.32 inches.

What symptoms indicate the power pack needs replacement? Hard starting, misfiring, rough idle, or a no-spark condition on a Johnson/Evinrude 3-cylinder outboard are common signs the power pack, such as the Sierra 18-99173, needs replacement.

Will the 18-99173 work on a 2-cylinder or 4-cylinder Johnson/Evinrude engine? No. The Sierra 18-99173 is built specifically for 3-cylinder Johnson/Evinrude engines and is not intended for 2-cylinder or 4-cylinder applications.

Does the 18-99173 fit both 60 HP and 75 HP engines? Yes, the Sierra 18-99173 covers 60, 70, and 75 HP Johnson/Evinrude 3-cylinder outboards from 1986-1990.

How do I confirm this power pack is correct for my engine? Check the OEM power pack number currently installed on your engine against the replacement numbers for the Sierra 18-99173: 763796, 583125, 582115, or 583143, before ordering.

Is a specific wiring harness or connector needed to install the 18-99173? The 18-99173 is designed to connect using the existing wiring harness on the applicable Johnson/Evinrude 3-cylinder engine; no separate harness is specified for this power pack.

What years of Johnson/Evinrude outboards is this power pack for? The Sierra 18-99173 is designated for Johnson/Evinrude 3-cylinder outboards from model years 1986 through 1990.