The Mercury Racing Ratchet Clutch Dog—often called the ratching clutch dog—is a critical internal gearcase component that helps the lower unit engage and hold gear under load. If you’re rebuilding a 2.5 Liter Sportmaster, Torquemaster, or 2.4 Liter CLE (Crescent Leading Edge) gearcase with the larger internal “big propshaft” setup, this is one of the parts that must match the correct shaft and internal stack.
This clutch dog is referenced as Mercury Racing OEM part number 52-42672T, and it’s also commonly searched or listed as 42672, 42672T, and 840242 (ratcheting clutch dog).
What the ratchet clutch dog does inside a Sportmaster, Torqmaster, or CLE
Inside the gearcase, the clutch dog works with the shift system to lock into gear. In performance applications—where shock loads, quick shifts, and high torque are common—the clutch dog’s engagement surfaces matter. A healthy dog helps deliver positive gear engagement and reduces the chance of slipping, rattling, or “kicking out” when you’re on the throttle.
On big-shaft Sportmaster, Torqmaster, and big-shaft CLE builds, correct internal fit is everything. That’s why matching the correct 52-42672T / 42672T / 840242 style dog to the correct shaft family is so important during a rebuild.
When to replace the clutch dog
Clutch dogs are wear items in any hard-run gearcase. As they wear, you can see symptoms like inconsistent engagement, difficulty staying in gear, or a gearcase that doesn’t feel as crisp under load. Many builders replace the dog proactively during a refresh because it’s far cheaper than tearing the gearcase down again after a slip or engagement problem shows up.
If your gearcase is already apart, replacing a questionable clutch dog is one of the smartest reliability upgrades you can make—especially on a Sportmaster or CLE used for performance boating.
Applications: Big internal propshaft 2.5 Sportmaster, 2.5 Torqmaster, and 2.4 CLE
This ratcheting clutch dog is specified for Mercury Racing 2.5L Sporty, Torq Master and Mercury 2.4L CLE (Crescent Leading Edge) lower units that use the larger internal big propshaft configuration. Because Sportmaster and CLE cases have multiple internal variations over the years, the safest confirmation is always your Mercury parts diagram and your propshaft/internal stack identification.
In the real world, these gearcases are commonly found on classic high-performance Mercury V6 outboards and builds commonly referenced by model families such as 2.5L (EFI) / (EFI-Offshore), 200 HP XS 6 CYL (2.5L), 200 EFI Pro Max / Super Mag, 225 EFI Pro Max / Super Mag, and 225X EFI Pro Max, along with many other 2.4L and 2.5L Mercury Racing and performance V6 combinations that run Sportmaster or CLE gearcases.
Part number cross-references and search terms
If you’re matching a service note, a gearcase parts list, or a shopping search, these names all commonly point to the same clutch dog family used in big-shaft Sportmaster/CLE builds:
Mercury Racing OEM: 52-42672T
Common variations: 42672, 42672T
Common listing name: 840242 ratcheting (ratching) clutch dog
Contact mike@buckshotracing77.com or +1-714-697-1716 with any questions.