Mercury 2-Stroke 13.5HP Outboard Marine Engine Parts

(11 products)

This page is dedicated to Mercury 2-Stroke 13.5HP outboard engines. Use it to find compatible parts and practical service information, including maintenance tips, common replacement items, and troubleshooting guidance. You can also browse our main Mercury collection for a wider selection. Scroll to the bottom of the page to start browsing parts for this engine, and remember you can use the “Filter & Sort” controls on the collection page to narrow results by horsepower, year range, and part category.

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How to Identify Your 13.5HP Model

Locate the serial/nameplate: typically on the swivel bracket (port or starboard) or on the transom bracket near the clamp screws.
Read the code and suffix: note shaft length (S=15" short, L=20" long), tiller vs. remote control, manual vs. electric start.
Confirm 2‑stroke configuration: carbureted models are common; verify whether your engine is premix or has oil injection (if equipped) before ordering fuel/oil system parts.
Use the serial number to choose parts: many small Mercury outboards have serial “breaks” where water pump, gearcase, and ignition parts change mid‑production.

Engine Overview

Mercury 13.5HP 2‑Stroke (Small-Outboard Family)

Feature	Description
Configuration	Carbureted 2‑stroke, small displacement single or twin cylinder with reed‑valve intake; short (15") and long (20") shaft options; manual start common, some with electric start.
Common Models	13.5HP 2‑stroke variants in multiple shaft lengths and control options; serial‑number ranges from older production years are frequently encountered—verify by serial before purchasing parts.
Advantages	Lightweight, simple fuel system, strong low‑to‑midrange for small boats, easy dockside serviceability.
Notes	Some components may share lineage with 9.9/15HP families but impellers, gearcase seals, and ignition parts can vary by serial break—use the serial plate to confirm compatibility.

Routine Maintenance & Service Parts

Intervals below are general guidelines for small 2‑stroke outboards. Always follow the service schedule and specifications in your official Mercury service manual.

Item	Interval*	Remarks	Parts Link
Gear oil (lower unit)	Every 100 hrs or annually	Check for water intrusion (milky oil) and metal debris; reseal if contamination is present.	Mercury Outboard Parts
Spark plugs	Inspect 50 hrs; replace yearly	Use correct heat range and gap; fouling often indicates rich mixture, excess oil, or prolonged idling.	Spark Plugs
Fuel filter / inline filter	Every 100 hrs or annually	Replace more often with ethanol fuel or if debris/water is found; inspect primer bulb and fuel lines.	Fuel Filters
Water pump impeller / kit	Every 2–3 seasons or 200 hrs	Replace sooner if weak tell‑tale, overheat alarm, or sandy/silty use; verify impeller and key size by serial number.	Mercury Water Pump Repair Kits
Anodes (sacrificial)	Inspect 50 hrs; replace at ≤50% remaining	Choose alloy for your water (aluminum for brackish/salt, magnesium for fresh, zinc for traditional salt).	Anodes
Premix ratio / oiling system	Check every use (premix); inspect annually (injection)	Most small Mercury 2‑strokes run 50:1 with TC‑W3 oil; confirm for your serial range. Inspect oil lines and primer for leaks.	Hoses
Propeller & hardware	Inspect each trip; grease splines seasonally	Remove fishing line, check hub for slip, verify cotter pin/locking hardware condition.	Propellers
Lower unit seal kit (as needed)	As needed (after leaks/milky oil)	Reseal if water intrusion is detected or after fishing‑line damage behind the prop. Confirm kit by serial break.	Mercury Lower Unit Seal Kits

Frequently Used Parts Categories

Routine Service – Mercury Outboard Parts
Cooling System – Mercury Water Pump Repair Kits
Fuel System – Fuel Filters
Ignition / Electrical – Electrical Items
Propulsion – Propellers
Gearcase Seals & Gaskets – Mercury Lower Unit Seal Kits
Corrosion Protection – Anodes

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak tell‑tale stream or overheat alarm	Clear salt/sand from tell‑tale, inspect impeller and intake screen; verify thermostat operation.	Water pump kit, thermostat, intake screen, gaskets
Poor acceleration / power loss	Check prop damage/slip, fuel quality, clogged filter, carb settings and compression.	Propeller, fuel filter, spark plugs, carb rebuild kit
Hard starting / rough idle	Verify choke/primer, check for air leaks at lines/bulb, inspect plugs and idle mixture.	Spark plugs, fuel line/primer bulb, carb gaskets
Excessive smoke (2‑stroke)	Confirm correct premix ratio and TC‑W3 oil, avoid extended cold idling, check thermostat.	Spark plugs, thermostat, reeds/gaskets
Gearcase noise / metal in oil	Inspect oil level and condition; check for fishing line behind prop; pressure test for seal leaks.	Gear oil, lower unit seal kit, bearings

FAQs

Are parts interchangeable between different years or similar small Mercury platforms?

Some fasteners and service items cross over, but water pump components, ignition parts, and gearcase seals often change at serial breaks. Always match by serial number and configuration (shaft length, start/steering options).

When should I replace the water pump impeller?

As a rule of thumb, every 2–3 seasons or about 200 hours—sooner if you notice a weak tell‑tale, overheat events, or if the engine has seen sandy or silty water.

How often should the lower unit gear oil be changed?

At least annually or every 100 hours. Inspect for milky color (water), burnt smell, or metal debris. If contaminated, reseal the gearcase before running again.

What information do you need to confirm that a part fits my 13.5HP?

Please provide the serial number from the nameplate, shaft length (15" or 20"), manual vs. electric start, tiller vs. remote control, and any known model year. Photos of the nameplate and the area of the part in question are very helpful.

Ready to find parts by horsepower, year, and model? Browse our main Mercury collection and use “Filter & Sort” to zero in on your Mercury 2‑Stroke 13.5HP components.

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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.