Sierra Rev Limiter 18-99365 for Mercury Mariner Outboard Engines

The Sierra 18-99365 is a rev limiter (RPM limiter) built for Mercury Mariner outboard engines. This component is part of the engine's ignition and speed-control circuit, protecting the powerhead from over-revving by limiting maximum engine RPM during operation. Rev limiters like this one are typically installed as a replacement for a worn or failed factory unit, restoring correct high-RPM cutoff behavior and helping prevent engine damage caused by prolonged over-speed operation.

Ordering by the exact Sierra part number ensures the replacement matches the electrical characteristics and mounting configuration of the original Mercury Mariner rev limiter it is designed to replace. It is a straightforward swap for technicians and DIY boat owners performing ignition system maintenance or troubleshooting an over-rev condition on a Mercury Mariner outboard.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-99365
• Product Type: RPM Limiter (Rev Limiter)
• Compatibility: Mercury Mariner outboard engines
• Weight: 0.7 pounds
• UPC: 808282398835

Fitment

• Mercury Mariner outboard engines

Frequently Asked Questions

What is the Sierra 18-99365? The Sierra 18-99365 is a rev limiter (RPM limiter) designed for Mercury Mariner outboard engines, used to cap maximum engine RPM as part of the ignition system.

What does a rev limiter do on an outboard engine? A rev limiter restricts an engine from exceeding a set maximum RPM, which helps protect the powerhead from damage caused by over-revving. The Sierra 18-99365 performs this function on compatible Mercury Mariner outboards.

Which engines does the Sierra 18-99365 fit? The Sierra 18-99365 is designed for Mercury Mariner outboard engines.

How much does the Sierra 18-99365 weigh? The Sierra 18-99365 rev limiter weighs 0.7 pounds.

Is the Sierra 18-99365 a genuine Sierra part? Yes, 18-99365 is the Sierra manufacturer part number for this rev limiter, not a third-party clone.

Is installation of the 18-99365 rev limiter something I can do myself? Installing the Sierra 18-99365 involves connecting it into the outboard's existing ignition wiring in place of the original rev limiter, a task suited to owners comfortable with basic outboard electrical work or a qualified marine technician.

Why would I need to replace my outboard's rev limiter? A failed or malfunctioning rev limiter can allow an engine to over-rev or can cause erratic running, so replacing it with the Sierra 18-99365 restores correct RPM-limiting function on compatible Mercury Mariner outboards.

What is included when I order the 18-99365? Ordering the Sierra 18-99365 includes the rev limiter unit itself, identified by UPC 808282398835.

Does the part number 18-99365 refer to a single specific part? Yes, 18-99365 is the Sierra manufacturer part number that identifies this specific rev limiter for Mercury Mariner outboard engines.

Is the Sierra 18-99365 used on inboard or sterndrive engines? No, the Sierra 18-99365 is designed for Mercury Mariner outboard engines.