Sierra Johnson/Evinrude Engine Adapter Harness 18-99401, Adapts 1976-1995 Engines to Deutsch Controls

The Sierra 18-99401 Engine Adapter Harness lets owners of older Johnson and Evinrude outboards connect to newer Deutsch-style control wiring without replacing the engine's original harness. It is built as a universal-fit adapter, bridging the older engine-side connector to the modern Deutsch connector used on updated control systems, so the two generations of wiring can be joined directly instead of splicing wires by hand.

The harness measures 18 inches in length, giving enough reach to route between the engine wiring and the control-side connection point during an install. On the control end it terminates in a DT Connector, matching the Deutsch connector style found on newer outboard control harnesses. It is supplied as a single adapter harness, ready to connect between the two systems once the correct connector orientation is confirmed for the specific engine.

This adapter is intended for 1976-1995 Johnson and Evinrude engines that need to interface with new Deutsch-style controls. Because fitment depends on the exact engine and control system being paired, buyers should confirm the connector configuration matches their engine before installing.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-99401
• Product Type: Engine Adapter Harness
• Compatibility: Johnson and Evinrude engines, 1976-1995
• Adapts To: New Deutsch-style engine controls
• Fit Type: Universal Fit
• Connector Type: DT Connector
• Harness Length: 18 inches
• Number of Items: 1
• Weight: 0.7 pounds

Fitment

• Johnson outboard engines, 1976-1995
• Evinrude outboard engines, 1976-1995

Frequently Asked Questions

What engines does the Sierra 18-99401 adapter harness fit? It is built for Johnson and Evinrude outboard engines from 1976-1995 that need to connect to newer Deutsch-style control wiring.

What does this harness actually do? The 18-99401 adapts the older engine-side wiring connector on 1976-1995 Johnson and Evinrude outboards to a new Deutsch-style connector, so the older engine can be wired into updated controls without re-splicing the factory harness.

How long is the Sierra 18-99401 harness? It measures 18 inches in length, end to end.

What type of connector is on the control end? The control-side end of the 18-99401 terminates in a DT Connector, matching the Deutsch connector style used on newer outboard control harnesses.

Is this a universal-fit part? Yes, the 18-99401 is described as a universal-fit adapter for 1976-1995 Johnson and Evinrude engines, but buyers should verify the connector configuration matches their specific engine before installing.

How much does the 18-99401 weigh? The Sierra 18-99401 adapter harness weighs 0.7 pounds.

How many pieces come with this part? The 18-99401 is supplied as a single adapter harness (one item).

Can I use this to upgrade an older Johnson or Evinrude to modern controls without rewiring the whole boat? That is its purpose: the 18-99401 lets a 1976-1995 Johnson or Evinrude engine plug into new Deutsch-style control wiring through the adapter harness instead of requiring the control harness to be rewired to the old connector style.

Does the 18-99401 include the Deutsch connector on both ends? It has a DT Connector on the control side to mate with new Deutsch-style controls, with the opposite end configured for the 1976-1995 Johnson/Evinrude engine-side connection.

Is Sierra part number 18-99401 the correct number to order? Yes, 18-99401 is the part number for this Johnson/Evinrude engine adapter harness.