Mercury 350HP 4-Stroke Outboard Marine Engine Parts

(15 products)

This page is dedicated to Mercury 4‑Stroke 350HP outboard engines. Use it to find compatible parts and service information, including maintenance tips, common replacement items, and troubleshooting guidance. You can also browse the main Mercury collection. Scroll to the bottom of the 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 350HP Model

Find the serial number plate on the starboard side of the transom bracket or swivel bracket. Record the full serial and any model designation (e.g., 350 Verado).
Model suffixes indicate shaft length (L/XL/XXL), steering/mid‑section type, and control type (DTS digital throttle/shift). These suffixes help determine exact parts.
Platform clues: Legacy Verado 350 uses an inline‑6 supercharged layout; the current 350 is a naturally aspirated V10. Cowling shape and the number of ignition coils can help you distinguish them.
Check the emissions/production label for the model year range and compliance family, which often aligns with specific service kits and filters.

Engine Platform Overview

Verado 350 Inline‑6 Supercharged (Legacy)

Feature	Description
Configuration	Inline‑6, supercharged, 4‑stroke EFI with digital controls (DTS); advanced mid‑section and integrated power steering on most variants.
Common Models	350 Verado L6 in L/XL/XXL shaft lengths; various AMS mid‑sections and gearcase options (standard or heavy‑duty).
Advantages	Very smooth operation, strong holeshot, integrated steering assist, proven reliability when maintained.
Notes	Many service parts (oil filter, anodes, gearcase seal kits, water pump kits) are unique to the L6 platform. Verify by serial number.

Verado 350 V10 (Current)

Feature	Description
Configuration	V10, naturally aspirated, 4‑stroke EFI with DTS; modern mid‑section and gearcase updates for efficiency and handling.
Common Models	350 Verado V10 in XL/XXL/XXXL shaft options; digital steering/advanced rigging on many boats.
Advantages	Broad torque curve, refined NVH, strong charging output, improved service access on many items.
Notes	Filters, anodes, and water pump kits differ from the legacy L6. Always match parts by platform and serial number.

Routine Maintenance & Service Parts

Intervals below are general guidelines for 4‑stroke outboards. Always follow the official Mercury service manual for your exact model and duty cycle.

Item	Interval*	Remarks	Parts Link
Engine oil + filter	100 hours or annually	Use FC‑W marine oil grade specified by Mercury; replace crush washer and torque per manual.	Oil Filters
Gear oil (lower unit)	100 hours or annually	Inspect for water intrusion and metal; replace drain/fill plug seals when servicing.	Mercury Outboard Parts
Spark plugs	300 hours or 3 years	Inspect condition and gap; replace sooner if misfire or heavy idling operation.	Spark Plugs
Fuel filter / water separator	100 hours or annually	Replace engine‑mounted and any remote 10‑micron filter; drain separator if contaminated.	Fuel Filters
Water pump impeller / kit	Every 2–3 seasons (or 300 hours)	Service more often in sandy/silty water or if weak telltale/overheat occurs.	Mercury Water Pump Repair Kits
Anodes (sacrificial)	Inspect 50 hours; replace as needed	Maintain at least ~50% material; match alloy to water type (fresh, brackish, salt).	Anodes

*Intervals are typical for recreational use; shorten for heavy commercial, high‑load, or harsh environments.

Frequently Used Parts Categories

Routine Service: Service & Maintenance Kits
Cooling System: Mercury Water Pump Repair Kits
Fuel System: Fuel Filters and Fuel Pumps
Ignition / Electrical: Starters, Rectifiers, Sensors
Propulsion: Propellers
Gearcase Sealing: Mercury Lower Unit Seal Kits
Corrosion Protection: Anodes

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak telltale or overheat alarm	Inspect intake screens for debris, thermostat function, and impeller condition.	Water pump kit, thermostat, intake screens, anodes (for corrosion hot spots)
Poor acceleration or power loss	Check propeller for damage/ventilation, replace clogged fuel filters, verify spark plug condition.	Propeller, fuel filter, spark plugs
Hard starting or rough idle	Confirm battery health and connections, primer bulb integrity, and look for vacuum leaks.	Spark plugs, fuel lines/hoses, sensors (IAT/MAP), starter
Charging or electronics warnings	Inspect battery voltage under load, harness grounds, and rectifier/regulator output.	Rectifier/regulator, wiring/terminals, sensors
Gearcase noise or metal in gear oil	Drain oil and inspect; check seals for leaks and prop shaft for line wrap.	Lower unit seal kit, bearings, propeller hardware

FAQs

Are parts interchangeable between the V10 350 and the older L6 350 Verado?

Many are not. Filters, anodes, water pump kits, and some sensors differ between platforms. Always confirm by serial number and model designation before ordering.

When should I replace the water pump impeller?

As a baseline, every 2–3 seasons or about 300 hours. Replace sooner if operating in sandy/silty water or if telltale is weak or temperature alarms occur.

How often should I change the gear oil?

Typically every 100 hours or annually. Change sooner after break‑in or if the engine has had an impact or suspected seal damage.

What information do you need to confirm compatibility?

Please provide the engine serial number, model name (e.g., Verado 350), shaft length, control type (DTS), and any gearcase notes (standard or heavy‑duty). Photos of the serial plate and the part location also help.

Ready to find parts by horsepower, year, and model? Browse the main Mercury collection and use the filters to narrow results for your 350HP.

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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.