When a fresh outboard rebuild turns over for the first time, there’s a short interval before full oil pressure develops and a hydrodynamic film forms. That boundary-lubrication interval is where Mercury’s Assembly and Needle Bearing Grease (OEM part 8M0071836) is intended to operate. The compound provides a persistent, high-film-strength layer, so metal surfaces are protected during the first few revolutions.
 
Formulated for both two-stroke and four-stroke outboard engines, the grease establishes a controlled film on critical interfaces so newly repaired or newly built parts don’t run dry at first crank. It is meant for assembly/service operations, mitigates startup wear, and disperses into the engine’s normal lubricant without adverse interaction once the engine is up to temperature.
 
Why assembly lube matters?
Two-stroke architectures depend on a fuel–oil mist to reach bearings; initial distribution is not instantaneous.
 
Four-stroke engines rely on pressurized galleries and splash, which require several seconds to build pressure and flow after reassembly.
 
In both cases, components such as cam lobes, lifter faces, rocker tips, wrist pins, and needle/roller elements experience load before hydrodynamic conditions stabilize.
 
An assembly grease with adequate tack and shear stability remains in place through static assembly, cranking, and first fire, reducing asperity contact and adhesive wear.
 
After the oil system takes over, the compound should dissolve or shear down into the circulating lubricant so it doesn’t persist as an obstruction.
 
Outboard Rebuild Use Cases
During top-end work, coat camshaft lobes and lifter faces so that relative motion occurs over a lubricated boundary film. F
 
For two-stroke small-end assemblies, lightly work the grease into the needle bearings and over the wrist pin and bore; rotating the bearing distributes the film and helps retain rollers during installation.
 
On four-strokes, a very thin film on cam journals, followers, rocker pivots, and timing wear points protects while you establish oil pressure. The same film offers short-term fretting and corrosion resistance when an engine must sit between assembly and first star t.
 
Instructions
Begin with cleanliness. Degrease and dry mating surfaces with oil-free air, verify clearances, and complete any dry-fit checks before applying lubricant.
 
Finger-apply a thin, continuous film to parts that carry load at startup: cam lobes and follower faces, rocker tips and pivots, wrist pins and their bores, and roller/needle elements.
 
For small-end assemblies, a light pack helps hold needle bearings in place during wrist-pin installation; avoid forcing excess into oil drillings. Keep lubricant away from oil jets, galleries, combustion chambers, friction linings, and sensor faces.
 
Rotate assemblies by hand to confirm uniform motion and coverage, then close the engine using the specified torque/angle procedures.
 
For four-strokes, prime the oil system per the service manual (e.g., prefill filter, disable ignition/injection, and crank to pressure, or use a pre-lube pump).
 
For two-strokes, verify premix or oil-injection functionality before first fire.
 
Bring the engine to temperature according to the break-in procedure; the assembly film will disperse without compromising the engine oil or premix.
 
Benefits
The technical benefit is reduced boundary-regime wear during cranking and early running: lifters slide without scuffing, cam lobes avoid micro-spalling, and needle elements resist brinelling.
 
The grease’s tack and persistence minimize squeeze-out during assembly and short-term storage, yet its dispersion characteristics allow it to clear once bulk oil flow is established.
 
This reduces the risk of blocked strainers, additive dilution, or residue that could bias early oil analysis. In practice, it supports stable initial idle, predictable break-in, and protection of freshly finished surfaces.
 
Compatibility and Best Practices
The product is suitable for two-cycle and four-stroke gasoline marine engines and common engine alloys, bushings, and elastomers. It is an assembly aid, not a substitute for in-service lubrication.
 
Apply only a visible film; more product increases the chance of obstructing clearances or passages. Keep the container sealed to prevent contamination, and follow the exact lubrication notes in the service manual for the engine family you’re building—some plain-bearing locations specify clean oil rather than grease, and those instructions take precedence.
 
FAQs
Can I use it on both two-stroke and four-stroke engines? Yes. It’s intended for both, including use on needle bearings, wrist pins, and valvetrain contact surfaces.
Will it contaminate engine oil or premix? No. It’s designed to provide boundary protection at startup and then disperse into the operating lubricant without adverse effects.
Should I still prime a four-stroke oil system? Yes. Assembly grease does not replace oil-system priming or pressure verification.
How much should I apply? A thin, uniform film over the working surface. Excess application can impede oil flow or alter clearances.
 
Contact Mike Hill with any technical questions at +1-714-697-1716 or mike@buckshotracing77.com