Mercury 4-Stroke 105HP Outboard Marine Engine Parts

(4 products)

This page is dedicated to Mercury 4‑Stroke 105 HP 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 the main Mercury collection, and at the bottom of this page you’ll find a quick path to start browsing parts for this engine. On the collection pages, use the “Filter & Sort” controls to narrow results by horsepower, year range, and part category/section.

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How to Identify Your 105 HP Model

Locate the serial number/nameplate on the transom bracket or swivel bracket. Photograph this tag before ordering.
Read the full model code and suffix: these often indicate shaft length, starting/controls (tiller vs. remote), and regional variations.
Confirm platform details: this 4‑Stroke class is typically inline‑4 EFI. Some 105 models are “Jet” variants; their pump and driveline parts differ from prop‑drive engines.
Match the serial range in your service manual when selecting tune‑up parts to avoid year‑to‑year supersession issues.

Platform Overview

Inline‑4 EFI 4‑Stroke (Prop‑Drive)

Feature	Description
Configuration	Inline‑4, EFI 4‑Stroke outboard in the ~100–115 HP class; quiet operation and strong mid‑range.
Common Models	Examples in this family include 100 HP EFI and 115 HP EFI 4‑Stroke models; many service items cross over within this range.
Advantages	Fuel‑efficient, low emissions, easy cold‑start behavior, and broad aftermarket parts support.
Notes	Tune‑up items (filters, plugs, anodes, impeller kits) are commonly shared within the inline‑4 EFI range. Always verify by serial number.

Jet‑Drive Variant (105 Jet)

Feature	Description
Configuration	Inline‑4 4‑Stroke powerhead driving a jet pump instead of a propeller; optimized for shallow‑water running.
Common Models	105 HP Jet 4‑Stroke listings are typical in Mercury catalogs for this class.
Advantages	Excellent in shallow or debris‑laden water; no exposed propeller.
Notes	Pump components (impeller/liner, reverse bucket) are unique to jet models. Powerhead maintenance (filters, plugs, anodes, cooling water pump) largely follows the inline‑4 EFI schedule.

Routine Maintenance & Service Parts

Intervals below are general guidelines for typical recreational use. Always follow the procedures and schedule in your official Mercury service manual.

Item	Interval*	Remarks	Parts Link
Engine oil + filter	100 hours or annually	Use FC‑W marine oil; warm the engine before draining. Replace crush washer as needed.	Oil Filters
Gear oil (lower unit)	100 hours or annually	For prop‑drive models; inspect for metal or water intrusion. Jet models service pump oil per manual.	Mercury Outboard Parts
Spark plugs	100 hours (inspect); 200 hours (replace) or per manual	Verify heat range and gap by serial range.	Spark Plugs
Fuel filter / water‑separating filter	Inspect 50 hours; replace annually	Drain water as needed; replace if contamination is present.	Fuel Filters
Water pump impeller / kit	Every 2–3 seasons or sooner if weak tell‑tale	Essential for cooling on both prop and jet variants (powerhead cooling circuit).	Mercury Water Pump Repair Kits
Anodes (sacrificial)	Inspect every 50 hours; replace at ~50% loss	Choose material for your water (zinc, aluminum, or magnesium).	Anodes
Lower unit seals (prop‑drive)	As needed (water intrusion, fishing‑line damage)	Pressure/vacuum test after service. Jet models use different pump seals.	Mercury Lower Unit Seal Kits

Frequently Used Parts Categories

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

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak tell‑tale or overheat alarm	Inspect intake screens for blockage; verify water pump impeller and thermostat function.	Water pump repair kit, thermostat, intake screen, anodes
Poor acceleration or power loss	Check for fouled spark plugs, clogged fuel filters, damaged propeller or (jet) worn liner/impeller.	Spark plugs, fuel filters, propeller (or jet pump wear components)
Hard starting or rough idle	Confirm battery voltage and connections; inspect plugs; drain/replace stale fuel; check for water in separator.	Spark plugs, fuel filters, electrical items
Gearcase noise or metal in gear oil (prop‑drive)	Verify gear oil level/condition; pressure test; inspect propshaft seals. For jet models, check pump bearings/liner.	Lower unit seal kits, propellers

FAQs

Are parts interchangeable between 100, 105 (Jet), and 115 HP 4‑Stroke models?

Many routine service items are shared across the inline‑4 EFI 4‑Stroke family, but drivetrain parts (prop vs. jet) and some serial‑range specifics can differ. Use your serial number to confirm fitment before ordering.

When should I replace the water pump impeller?

As a rule of thumb, every 2–3 seasons for recreational use, or immediately if the tell‑tale weakens, the engine overheats, or the impeller shows wear from sand/silt.

How often should I change lower unit gear oil?

Typically every 100 hours or once per season. Inspect for water (milky oil) or metal. Jet‑drive models use a different pump service procedure—follow the jet pump maintenance schedule in the manual.

What information helps confirm compatibility?

Provide the engine serial number, full model code, horsepower, shaft length, and clear photos of the nameplate and the part you’re replacing.

Ready to find parts for your Mercury by horsepower, year, and model? Start in our main Mercury collection and use the filters to narrow your results.

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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.