DeWalt XR DCMWP134N Lawn Mower Manual

The DeWalt XR DCMWP134N is a 54V MAX* cordless walk-behind lawn mower featuring a 21-inch steel deck, brushless motor technology, dual-port rapid charger, two 9.0Ah FLEXVOLT® batteries, 6-position single-lever cutting height adjustment (1.5-4 inches), 2-in-1 mulching and rear bagging capability, LED headlights, and a foldable handle for compact storage. This manual covers safety, assembly, operation, maintenance, and troubleshooting for optimal performance.

1. Features at a Glance 2. Assembly Instructions 3. First-Time Setup 4. Specifications 5. Controls and Operation 6. Cutting & Mulching 7. Battery & Charging 8. Maintenance 9. Storage 10. Safety Information 11. Troubleshooting

Features at a Glance

Key components: 21-inch steel cutting deck, Brushless Motor, FLEXVOLT® Battery System, Dual-Port Rapid Charger, 6-position height adjustment lever, 2-in-1 mulch/bag system, LED headlights, foldable handle, rear discharge chute.

Feature	Description
Power Source	Two 54V MAX* FLEXVOLT® 9.0Ah Batteries (included)
Cutting Width	21 inches
Cutting Height	1.5 to 4 inches (6 positions)
Deck Material	Powder-coated steel
Motor Type	Brushless (maintains power, longer runtime)
Charging System	Dual-port rapid charger (charges both batteries simultaneously)
Cutting Options	2-in-1 (mulch or rear bag)
Handle	Foldable for compact storage
Headlights	LED for low-light conditions
Safety Key	Removable key to prevent accidental start

Assembly Instructions

Unpack all parts and inspect for damage. Assembly requires basic tools (included).

Attach the lower handle: Align lower handle brackets with deck mounts; secure with provided bolts and wrench.
Install the upper handle: Slide upper handle into lower handle tubes; secure with knobs or bolts.
Attach the grass bag: Hook bag frame onto rear deck mounts; ensure it clicks into place.
Install mulch plug (if mulching): Insert mulch plug into rear discharge opening.
Install batteries: Insert both FLEXVOLT® batteries into battery ports; ensure they click and are secure.

WARNING! Do not install batteries until assembly is complete. Ensure all fasteners are tight.

First-Time Setup

Before first use, charge batteries fully and perform a safety check.

Charge batteries: Plug dual-port charger into outlet; insert both batteries. Charging complete when LEDs turn green.
Adjust cutting height: Move single lever to desired height (recommend 3 inches for first mow).
Select cutting mode: Install mulch plug for mulching or attach grass bag for collection.
Insert safety key: Insert key into slot near handle; mower will not start without it.

CAUTION! Always remove safety key when not in use. Keep hands and feet away from cutting blade.

Specifications

Model: DeWalt XR DCMWP134N
Power: 54V MAX* FLEXVOLT® Battery System
Battery: Two 9.0Ah FLEXVOLT® Batteries (included)
Cutting Width: 21 inches
Cutting Height Range: 1.5 - 4 inches (6 positions)
Deck: 21-inch steel, powder-coated
Motor: Brushless
Charger:Dual-port rapid charger (included)

Weight (without batteries): 65 lbs

Cutting Options: Mulch, Rear Bag

Warranty: 3-year limited warranty

Controls and Operation

Start/Stop: Press and hold safety lever on handle; push start button. Release lever to stop blade.

Handle Controls: Safety lever, Start button, Battery fuel gauge, Height adjustment lever.

Operation: Walk at steady pace; overlap passes slightly. Avoid mowing wet grass. Use LED headlights in low light. For slopes, mow across slope, not up and down.

Cutting & Mulching

Mulching: Install mulch plug; cut grass into fine clippings that decompose into lawn.

Ensure grass is dry and not too tall.

Set cutting height appropriately (remove no more than 1/3 of grass height per mow).

Mow at steady pace; clippings will be recut and dispersed.

Bagging: Attach grass bag; collect clippings for disposal.

Tip: Keep blade sharp for clean cuts and efficient mulching.

Battery & Charging

FLEXVOLT® Batteries: Two 9.0Ah batteries provide extended runtime. Charger: Dual-port rapid charger.

Charging: Insert batteries into charger; plug into 120V outlet. LED indicates charging (red) and complete (green).

Runtime: Approx. 60 minutes per charge (varies with grass conditions).

Storage: Store batteries in cool, dry place; charge fully before long storage.

WARNING! Use only DeWalt FLEXVOLT® batteries and charger. Do not expose batteries to fire or water.

Maintenance

Regular maintenance ensures longevity and performance.

Blade sharpening: Sharpen or replace blade every season or when dull.

Deck cleaning: After each use, disconnect batteries and clean underside with brush or hose.

Battery care: Keep terminals clean; store at room temperature.

Wheel inspection: Check wheels for damage; lubricate axles if needed.

CAUTION! Always remove safety key and batteries before performing maintenance.

Storage

End-of-season or long-term storage steps.

Clean mower thoroughly; remove all grass clippings.

Charge batteries fully; store separately in cool, dry place.

Fold handle: Loosen knobs, fold handle down for compact storage.

Store in dry location, protected from elements.

Tip: Apply light oil to blade to prevent rust during storage.

Safety Information

Read all safety warnings before operation.

Wear safety glasses, long pants, and sturdy shoes.

Clear mowing area of debris, rocks, and toys.

Do not mow wet grass or on steep slopes.

Keep bystanders, especially children and pets, away.

Never remove safety key while blade is moving.

Use only as intended; no modifications.

DANGER! Blade can cause severe injury. Always disconnect batteries before servicing.

Troubleshooting

Symptom Possible Cause Corrective Action

Mower won't start Safety key not inserted, dead batteries Insert safety key; charge or replace batteries.

Poor cutting performance Dull blade, low battery, wet grass Sharpen/replace blade; charge batteries; mow when grass is dry.

Uneven cut Uneven tire pressure, incorrect height setting Check tire pressure; adjust cutting height evenly on all wheels.

Battery not charging Faulty charger, dirty terminals Check charger connection; clean battery terminals with dry cloth.

Excessive vibration Damaged or unbalanced blade Stop immediately; inspect blade for damage; replace if necessary.

Service: For repairs, contact authorized DeWalt service center. Do not attempt to repair motor or electronics.

Support: 1-800-4-DeWalt (1-800-433-9258); www.dewalt.com

DeWalt XR DCMWP134N Lawn Mower Manual © - All Rights Reserved 2025

Symptom	Possible Cause	Corrective Action
Mower won't start	Safety key not inserted, dead batteries	Insert safety key; charge or replace batteries.
Poor cutting performance	Dull blade, low battery, wet grass	Sharpen/replace blade; charge batteries; mow when grass is dry.
Uneven cut	Uneven tire pressure, incorrect height setting	Check tire pressure; adjust cutting height evenly on all wheels.
Battery not charging	Faulty charger, dirty terminals	Check charger connection; clean battery terminals with dry cloth.
Excessive vibration	Damaged or unbalanced blade	Stop immediately; inspect blade for damage; replace if necessary.