This water pump impeller and top gasket maintenance kit from Buckshot Racing #77 is for Mercury/Mariner V6 raw-water pumps comprising the OEM-equivalent impeller (89984T4) and pump base gasket (858524). It’s intended for annual/100-hour service where the pump housing, cup, and wear plate remain within spec.
 
Applications
Engineered for Mercury/Mariner 80–300 HP outboards and sterndrives, covering production 2.0/2.4/2.5 Liter Mercury V6 gearcases as well as CLE, 2.5L Sportmaster, 2.5 Torque Master, (F1 S3000, APEX SSM #4, SST-120 SSM #6, less gasket) and standard “fishing” lowers. The same geometry serves Force 85–150 HP and MerCruiser MC-I R/MR/Alpha I (~1970–1990) installations using this pump pattern.
 
What’s included (and why)
Impeller 89984T4 — restores vane elasticity and volumetric efficiency for reliable priming and idle flow.
Base gasket 858524 — re-establishes the low-pressure boundary under the wear plate; critical for suction and quick prime.
 
Housing/cup/plate are not included; reuse them if flat, smooth, and undistorted.
 
Service Interval
Replace yearly or ≤100 hours. Elastomer set, heat glazing from dry starts, and abrasive tip wear reduce swept volume first at idle. The impeller and base gasket are the primary wear/seal elements; other hardware is replaced only on inspection.
 
Use this kit when:
The stainless wear plate is flat (no fingernail-catch grooves).
The cup/housing shows uniform contact with no melt or waviness.
The outlet grommet cleanly grips the water tube.
If these conditions aren’t met—or flow remains weak after replacement—escalate to a housing/cup/plate kit.
 
Installation notes (high level)
Install the base gasket dry and aligned; lubricate cup/impeller with water or silicone-safe lube.
Seat the hub on the shaft key and lower the housing while rotating the driveshaft in the engine’s forward direction to set vane bend.
Torque fasteners evenly.
On reassembly, ensure positive water-tube engagement and verify a prompt, steady tell-tale on a tank or high-flow muffs.
 
Cross-reference (impeller families)
Also seen as: F694065, 18-3017, 30221, 65960, 8M0028376, 803631T, 85460, 89840, 89984, 89984B1, 89984B2, 89984B3, 89984T3, 899841, 899842, 899843, 899844, 9-45306, 858524, 30604, 31020, 3243450, 883785609, 85609B1, 856091, 858524, 9-60035.
 
The Water Pump Impeller + Gasket Kit (Mercury 89984T4 + 858524) from Buckshot Racing #77 targets the two wear/seal items that govern pump readiness and idle-speed throughput on Mercury/Mariner V6 (1976–2005) and listed Force/MerCruiser equivalents—ideal for seasonal/100-hour service when hard parts remain in tolerance.
 
Includes one (1) Mercury / Mariner / Force Water Pump Impeller + one (1) replacement base gasket.
 
Contact Mike Hill with any tech questions at +1-714-697-1716 or mike@buckshotracing77.com