Mercury 135HP 2-Stroke Outboard Engine Parts

(59 products)

Dedicated to Mercury 2‑Stroke 135 HP outboard engines, this page helps you identify compatible replacement parts and plan routine service. Below you’ll find maintenance tips, frequently used parts, and troubleshooting guidance. You can also browse the main Mercury collection for a wider selection. Scroll to the bottom 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 135 HP Model

Locate the serial/model tag on the swivel bracket (port or starboard). Some engines also have an instruction plate above the steering tube with serial data.
Model codes often begin with 1135… followed by letters/numbers that denote year, shaft length, and starting/controls. Record the full code and serial for accurate parts matching.
Mercury 135 HP 2‑Stroke engines were produced across multiple years (commonly late 1980s through mid‑2000s). Visual cues: carbureted/EFI V6 vs. later Direct‑Fuel‑Injection (DFI) variants.
Confirm gearcase type and shaft length, as propellers, water pump kits, and seals can vary by lower unit and model year.

Platform Overview

V6 2‑Stroke (Carbureted/EFI)

Feature	Description
Configuration	V6 2‑Stroke, typically carbureted (earlier years) or EFI; compact gearcase options.
Common Models	Examples include model codes beginning 1135… from late 1980s through late 1990s.
Advantages	Strong mid‑range power, relatively light weight for a 135 HP class V6.
Notes	Ignition, fuel delivery, and cooling parts can vary by year. Verify serial/model before ordering.

V6 2‑Stroke (DFI/OptiMax)

Feature	Description
Configuration	V6 2‑Stroke Direct Fuel Injection (OptiMax) on later 135 HP models.
Common Models	Late 1990s to mid‑2000s variants; model codes also start with 1135… followed by platform/year suffixes.
Advantages	Improved fuel economy and emissions vs. carb models; strong overall performance.
Notes	DFI‑specific fuel, air, and sensor components differ from carb/EFI engines. Confirm DFI vs. carb platform before purchase.

Routine Maintenance & Service Parts

Intervals below are general guidelines for Mercury 2‑Stroke 135 HP engines; always defer to your official service manual and local operating conditions.

Item	Interval*	Remarks	Parts Link
Gear Oil (Lower Unit)	Every 100 hrs or annually	Inspect for metal or water intrusion; replace seals if milky oil is found.	Mercury Outboard Parts
Spark Plugs	Inspect each season; replace ~100 hrs	Gap to spec; replace fouled or worn plugs to restore idle and acceleration.	Spark Plugs
Fuel Filter / Inline Filter	100 hrs or annually	Replace more often with ethanol fuel or storage; check for water/debris.	Fuel Filters
Water Pump Impeller / Kit	Every 2–3 seasons or 100 hrs	Replace sooner if weak tell‑tale or overheat alarm occurs.	Mercury Water Pump Repair Kits
Anodes (Trim Tab/Block/External)	Inspect every 50 hrs; replace as needed	Use the correct alloy for fresh, brackish, or saltwater to prevent corrosion.	Anodes
Oil Injection System Check (2‑Stroke)	Seasonally	Verify pump operation, lines, and filters; premix backup only per manual if required.	Mercury Outboard Parts
Thermostats	Inspect annually; replace if sticking	Stuck‑open stats can cause cold‑running and carbon build‑up; stuck‑closed may overheat.	Mercury Outboard Parts
Propeller & Hub	Inspect each trip; service seasonally	Check for dings and fishing line; verify hub integrity to prevent cavitation/slip.	Propellers
Gearcase Seals (if water found)	As needed	If gear oil is milky, pressure/vacuum test and reseal the lower unit.	Mercury Lower Unit Seal Kits

*Intervals may vary with usage, environment, and specific model year/platform.

Frequently Used Parts Categories

Cooling System: Mercury Water Pump Repair Kits
Gearcase & Seals: Mercury Lower Unit Seal Kits
Fuel System: Fuel Filters and Fuel Pumps
Ignition & Starting: Spark Plugs and Starters
Corrosion Protection: Anodes
Propulsion: Propellers and Propeller Guards
Accessories & Setup: Outboard Hydrofoil Stabilizers and Boat Accessories

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak tell‑tale or overheat alarm	Inspect intake screens, thermostats, and impeller condition	Water pump kit, thermostat(s), intake screen
Poor acceleration / power loss	Check spark plug condition, fuel filters, and prop hub integrity	Spark plugs, fuel filter, propeller/hub
Hard starting / rough idle	Verify fuel quality, primer bulb, and air leaks; inspect plugs and idle settings	Spark plugs, fuel lines/hoses, inline filter
Excessive smoke (2‑Stroke)	Confirm correct oiling (injection or premix), check for stuck thermostat (cold‑running)	Oil injection components, thermostat, plugs
Gearcase noise / metal in oil	Drain and inspect gear oil; pressure test for seal leaks	Gear oil, lower unit seal kit, bearings

FAQs

Are parts interchangeable between different years or platforms?

Not always. Carb/EFI and DFI (OptiMax) 2‑Stroke platforms use different fuel, ignition, and sensor components. Confirm your full model and serial to ensure fit.

When should I replace the water pump impeller?

As a rule of thumb, every 2–3 seasons or about 100 hours. Replace sooner if the tell‑tale weakens, the engine overheats, or the impeller shows wear.

How often should I change lower unit gear oil?

Inspect and replace every 100 hours or annually. If oil appears milky or metallic, pressure test and reseal the gearcase before further use.

What information do you need to confirm part compatibility?

Provide the engine’s model and serial numbers, shaft length, controls (tiller/remote), and any notes about carb/EFI or DFI. Photos of the nameplate and the existing part also help.

Ready to find parts by horsepower, year, and model? Browse the main Mercury collection to start narrowing results for your 135 HP 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.