Mercury Quicksilver 19453T Water Pump Impeller — 30–60 HP FourStroke / Force 75 HP Outboard

Mercury Quicksilver 19453T — Water Pump Impeller, 30–60 HP FourStroke / Force 75 HP Outboard

Overview

Mercury Quicksilver 19453T is a genuine OEM high-volume, long-vane water pump impeller for selected Mercury, Mariner, and Force outboard cooling systems. It mounts on the driveshaft inside the lower-unit water pump housing and supplies cooling water to the engine. Mercury uses Mercury-grade elastomer blades designed for flexibility across marine operating temperatures, with a reinforced center insert to resist tearing and hub separation. It is the current replacement for the earlier impeller 19453 / 47-19453.

Fitment note: Mercury used different impellers across closely related 30–60 HP gearcases. Engine family and displacement alone are not sufficient to confirm the correct water pump part. Always verify by exact horsepower, model, and serial number using the Mercury parts catalog water-pump assembly diagram.

Compatible Applications

• Mercury 30–60 HP 3-cylinder FourStroke outboard — serial 1C049739 and up (confirm by diagram)
• Mercury 40–60 HP 4-cylinder FourStroke carbureted outboard — serial range 0G765581–0T583552 (confirm by diagram)
• Mercury 40–60 HP 4-cylinder FourStroke EFI outboard — serial range 0T184587–1C050251 (confirm by diagram)
• Force 75 HP outboard — serial range 0E288000–0E344999 (confirm by diagram)
• Selected Mercury / Mariner 45 Jet, 50, 55, and 60 HP 3-cylinder outboards — depending on serial range (confirm by diagram)
• Always confirm by exact engine model and serial number — impeller specifications vary across similar gearcase families

Service Interval

Mercury recommends inspecting and replacing the water pump impeller every 300 hours or 3 years, whichever comes first — or sooner if any symptoms of reduced cooling are present. Impeller blades harden and lose flexibility over time even without visible damage, which reduces pump efficiency before failure becomes obvious. Replace proactively rather than waiting for symptoms.

When to Replace

• At scheduled 300-hour or 3-year water pump service intervals
• Impeller blades are cracked, permanently bent, torn, missing material, or hardened
• Engine is running warmer than normal or overheating under load
• Reduced cooling-water output at the tell-tale / pee hole
• Engine with unknown service history — inspect the impeller before the next season
• After an overheating event — inspect for heat-damaged blades even if the impeller appears intact

Installation Notes

• Remove the lower unit and water pump housing according to the applicable Mercury service procedure for the exact engine model and serial range
• While the pump is open, inspect the pump housing bore for scoring or wear, the wear plate (face plate) for grooves, the drive key, and all gaskets and seals — replacing all worn components in the same service avoids having to re-open the pump shortly after
• The impeller drive key is a separate component on applicable assemblies and is not included with the bare impeller — inspect it and replace if worn or damaged
• Lubricate the impeller blades and housing bore lightly before installation to reduce initial dry-start wear
• Install the impeller with the blade curvature in the correct rotation direction as specified in the Mercury service manual — an impeller installed backwards will not pump correctly
• Replace all pump gaskets and seals at the same time — see the Water Pump Repair Kit 42089A5 for a complete pump rebuild kit option
• After reassembly, verify cooling-water output at the tell-tale before putting the engine under load

Technical FAQ

• What is the difference between 19453T and the earlier 19453? 19453T is the current active Mercury OEM part number that supersedes the original 19453 / 47-19453. It is the correct current replacement for any application that previously used 19453. If your service records or diagram show 47-19453, order 19453T.
• Can I use a generic aftermarket impeller instead of the OEM Mercury part? Not recommended for these applications. The vane length, hub diameter, elastomer compound, and center insert design of the OEM impeller are calibrated for the specific pump housing geometry and cooling demand of the engine. A generic impeller with different vane stiffness or slightly different OD can reduce pump output, fail faster, or cause hub separation. For a high-volume pump in a 40–60 HP application, the OEM specification matters.
• How do I know if my impeller needs replacement before it fails? Pull the lower unit and inspect the impeller during your seasonal service. Signs of impending failure include blades that are stiff and don’t spring back when bent, small cracks at the blade roots or tips, a discolored center insert, and any evidence of previous overheating (scorched housing bore, heat-glazed blades). An impeller that has been in service for 3+ years or 300+ hours should be replaced regardless of appearance.
• Should I replace the housing and gaskets at the same time as the impeller? Yes, in most cases. A scored pump housing bore will damage the new impeller blades quickly. If the housing shows wear, replace it along with the impeller, gaskets, and seals. The Water Pump Repair Kit 42089A5 includes the housing, gaskets, and related components for a complete service.
• What is the correct tell-tale output after water pump service? The tell-tale stream should be steady and continuous when the engine is running. A weak, intermittent, or absent stream after pump service indicates either an installation issue (impeller installed backwards, drive key missing, housing damage) or an air lock in the cooling circuit. Recheck before operating under load.

Part Numbers & Supersession

• Current Mercury OEM: 19453T / 47-19453T
• Supersedes: 19453 / 47-19453

Related Products

• Mercury MerCruiser Quicksilver Water Pump Repair Kit 42089A5
• Mercury 40–60 HP FourStroke EFI 100-Hour Maintenance Kit — 8M0232733
• Mercury Quicksilver 300-Hour Service Kit 8M0090559 — 40–60 HP FourStroke EFI Command Thrust
• Mercury Water Pump Gasket 858524 — MerCruiser Alpha One & Outboard
• Mercury Quicksilver 192043 Water Pump Base Gasket — 6–15 HP Outboard

Parts Desk Insights

Best Use Case: This impeller is the correct OEM replacement for the water pump on Mercury 30–60 HP FourStroke and Force 75 HP outboards where the parts diagram calls for 19453T / 47-19453T. It’s most commonly needed at scheduled 300-hour or 3-year water pump service, or when an engine is overheating and the impeller is identified as the cause. For a complete pump rebuild, order the Water Pump Repair Kit 42089A5 alongside this impeller to replace the housing, gaskets, and seals in the same visit.

Common Issues: The most frequent mistake is replacing only the impeller while leaving a scored pump housing in place — a damaged housing bore will destroy new impeller blades within a short period of use. Always inspect the housing bore during the service and replace it if worn. The second common issue is not confirming the serial number before ordering — Mercury used different impellers across similar 30–60 HP gearcase families, and the engine horsepower alone is not sufficient to confirm the correct part. Use the serial-number-specific diagram to confirm 19453T before ordering.