Sierra 18-7677 Knock Sensor, Replaces R020027, Fits MerCruiser MCM/MIE GM V-8 305, 350 and 377 CID Engines

The Sierra 18-7677 Knock Sensor is a detonation sensor built to meet the demands of high horsepower marine engines operating in the harsh marine environment. It is engineered to meet or exceed the original equipment part it replaces, giving boat owners a reliable option for restoring accurate detonation detection on applicable GM-based inboard and sterndrive engines. Sierra supplies OEM engine manufacturers and boat builders with quality parts, and this knock sensor is built to that same standard.

This sensor is designed for MerCruiser MCM/MIE applications using GM V-8 305, 350 and 377 CID engines. It mounts via a flange mount configuration and uses a glass sensor body with an analog output type. The compact housing measures 0.39 x 0.39 x 0.39 inches, making it a direct functional replacement for the original detonation sensor on these engine platforms. Every Sierra part is backed by Sierra's customer satisfaction warranty.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-7677
• Product Type: Knock Sensor
• Material: Glass
• Mounting Type: Flange Mount
• Output Type: Analog
• Item Dimensions: 0.39 x 0.39 x 0.39 inches
• Weight: 0.22 pounds
• UPC: 808282287405

Fitment

• MerCruiser MCM/MIE GM V-8 305, 350 and 377 CID engines

Replaces (OEM)

• R020027

Frequently Asked Questions

What engines does the Sierra 18-7677 knock sensor fit? The Sierra 18-7677 knock sensor is designed for MerCruiser MCM/MIE applications using GM V-8 305, 350 and 377 CID engines.

What OEM part number does the 18-7677 replace? It replaces OEM number R020027, so any application originally fitted with R020027 can use the Sierra 18-7677 as a direct replacement.

What is the 18-7677 knock sensor made of? The sensor body is made of glass, housed in a compact flange-mount design measuring 0.39 x 0.39 x 0.39 inches.

How much does the Sierra 18-7677 knock sensor weigh? This knock sensor weighs 0.22 pounds.

How does the knock sensor mount to the engine? The 18-7677 uses a flange mount configuration for installation on compatible GM V-8 marine engines.

What type of output does the 18-7677 knock sensor produce? This sensor produces an analog output signal, matching the original equipment detonation sensor it replaces.

Is the Sierra 18-7677 a genuine OEM part or aftermarket? It is a Sierra-manufactured part engineered to meet or exceed the specifications of the original equipment sensor (R020027) it replaces, sold as a quality aftermarket replacement.

What is included when ordering the 18-7677? The order includes one Sierra 18-7677 Knock Sensor, ready to install in place of the original R020027 sensor.

Does the 18-7677 knock sensor come with a warranty? Yes, the Sierra 18-7677 knock sensor is covered under Sierra's customer satisfaction warranty.

Will the 18-7677 knock sensor work on any GM V-8 marine engine? It is intended for MerCruiser MCM/MIE GM V-8 engines in the 305, 350 and 377 CID range specifically, rather than being a universal fit across all GM V-8 marine engines.