Mercury 2-Stroke 50HP Outboard Marine Engine Parts

(100 products)

This page is for Mercury 2‑Stroke 50HP outboard engines and helps you find compatible parts and service information. Below you’ll find maintenance tips, common replacement parts, and troubleshooting guidance. You can also browse the main Mercury collection. Scroll to the bottom of this page to start browsing parts for this engine. On the collection page, use the Filter & Sort controls to narrow results by horsepower, year range, and part category/section.

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How to Identify Your 50HP Model

Serial plate location: Look on the starboard side transom/clamp bracket or under the cowl on the swivel bracket. Record the full serial number and model designation.
Reading the model code: Mercury 2‑Stroke models often include letters for features (e.g., E = electric start, L = long shaft, PT = power trim). Example formats like “50ELPTO” exist; always match your exact serial range.
Platform check: This page covers 2‑Stroke 50HP engines. These typically have three spark plug leads and carburetors. 4‑Stroke models have an engine oil filter and different service parts.
Oil system: Some units use separate oil injection (e.g., Auto‑Blend); others are premix. Confirm whether your engine is oil‑injected or premix before ordering service items.

Engine / Platform Overview

Mercury 50HP Inline‑3 2‑Stroke (Carbureted)

Feature	Description
Configuration	Inline‑3, carbureted 2‑Stroke; some models equipped with oil‑injection (Auto‑Blend) and choke solenoid.
Common Models	Examples include 50HP 3‑cylinder 2‑Stroke variants (e.g., codes similar to 50EL, 50ELPT/ELPTO). Mariner‑badged equivalents share many components.
Advantages	Light weight, simple mechanical systems, strong mid‑range for small craft, broad aftermarket parts availability.
Notes	Always match parts to serial range and shaft length. Water pump and gearcase components are routine service items; oil‑injection hoses/filters should be inspected on injected models.

Routine Maintenance & Service Parts

Intervals below are general guidelines; always follow the official service manual for your exact serial range and operating conditions.

Item	Interval*	Remarks	Parts Link
Gear oil (lower unit)	Every 100 hrs or annually	Check for water (milky oil) and metal. Replace gaskets on fill/drain screws as needed.	Mercury Lower Unit Seal Kits
Spark plugs	Every 100 hrs or annually	Inspect color and gap; replace if fouled or worn. Use the plug type specified for your serial range.	Spark Plugs
Inline fuel filter	Every 100 hrs or annually	Replace to protect carburetors from debris and varnish. Verify flow direction.	Fuel Filters
Water pump impeller/kit	Every 2 seasons or ~200 hrs	Critical for cooling. Replace impeller more often in sandy/silty water or if tell‑tale is weak.	Mercury Water Pump Repair Kits
Anodes (sacrificial)	Inspect often; replace when ≥50% worn	Use the correct alloy for your water (fresh, brackish, or salt). Keep clean for best protection.	Anodes
Oil‑injection system (if equipped)	Every season	Inspect tank, lines, strainers, and warning circuits. Replace aged hoses; bleed per manual after service.	Hoses
Carburetor clean/sync	As needed; after storage	Ethanol fuel can varnish jets. Clean and synchronize multi‑carb linkage for smooth idle.	Carburetor Parts
Propeller & hub inspection	Every 50–100 hrs	Check for nicks and hub slip; remove prop periodically to clear line and grease splines.	Propellers
Premix fuel ratio (non‑injected)	Each refuel	Follow the manual; many Mercury 2‑Strokes of this class use 50:1 (gas:TC‑W3 oil). Do not premix if oil‑injected.	Mercury Outboard Parts

Frequently Used Parts Categories

Routine Service: Service & Maintenance Kits
Cooling System: Mercury Water Pump Repair Kits
Gearcase & Seals: Mercury Lower Unit Seal Kits
Fuel System: Fuel Filters
Ignition / Electrical: Starters
Propulsion: Propellers
Corrosion Protection: Anodes

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak tell‑tale or overheat alarm	Inspect intake screens for blockage; verify impeller condition; confirm hose routing and thermostat operation.	Water pump kit, gaskets, intake screens, thermostat
Hard starting / rough idle	Prime the bulb; verify choke/primer operation; check for stale fuel; inspect spark plug condition and carb sync.	Fuel filter, carburetor kit/cleaning items, spark plugs
Poor acceleration / power loss	Check prop for damage or hub slip; confirm full throttle opening; test compression and fuel supply.	Propeller/hub, fuel pump, filters, carburetor components
Excessive smoke (2‑Stroke)	Normal on cold start; verify premix ratio or oil‑injection function; ensure choke isn’t stuck on.	Oil lines/hoses, carb settings/needles, choke solenoid parts
Gearcase noise / metal in gear oil	Drain and inspect lube; look for water intrusion; check prop shaft for fishing line; verify seal condition.	Lower unit seal kit, bearings, seals, drain/fill screw gaskets

FAQs

Are parts interchangeable across different years or Mercury/Mariner versions?

Many components interchange, but Mercury uses serial ranges that can change small details. Match parts to your exact serial number and shaft length. Mariner‑badged engines of the same platform often share the same service parts.

When should I replace the impeller?

As a rule of thumb, replace the impeller every 2 seasons or ~200 hours, and sooner if you see a weak tell‑tale, run in sandy water, or the engine overheats.

How often should I change the gear oil?

Change lower unit gear oil every 100 hours or annually. Inspect for milkiness (water) and metal shavings; replace drain/fill gaskets each service.

What information helps confirm compatibility?

Provide the full serial number, model code, shaft length (S/L/XL), control type (tiller/remote), and whether the engine is oil‑injected or premix.

Ready to find parts? Browse the main Mercury collection and filter by horsepower, year, and model to get the right fit for your 50HP 2‑Stroke.

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If you’re unsure about your model, send us a photo of the nameplate and the part you need and we’ll help verify compatibility.