MJ504M 16-Inch Manual Quad-Wheel Reel Mower Sun Joe® MJ504M Manual Reel Mower | Product Guide Quiet, gas-free mowing powered by you.The Sun Joe® MJ504M 16-Inch Manual Reel Mower is a lightweight walk-behind push mower designed for small to medium lawns. It uses a 16-inch cutting path, 5 sharpened steel RAZOREEL blades, quad-wheel design, and 9-position height adjustment to help deliver a clean, precise cut without gas, oil, fumes, charging, or tune-ups.🌱 Manual Push Power🚫 No Gas or Oil🔧 Low MaintenanceMeet the MJ504MKey Components🖐️Foam grip — comfortable handhold for push mowing⬆️Upper handle — main handle section used while mowing🔩Handle knobs + bolts — secure the upper, middle, and lower handle sections↕️Middle handle bars — connect the upper handle to the lower handle⬇️Lower handle — attaches the handle assembly to the mower body📏Height adjustment levers — set cutting height across 9 positions🛞Quad wheels — two front wheels and two rear wheels for maneuvering✂️5 steel blades — RAZOREEL cutting system for manual mowingTechnical SpecificationsSpecificationMJ504MProduct TypeManual quad-wheel reel mowerBest UseSmall to medium lawnsPower TypeManual pushDrive TypeWalk-behind push mowerCutting Width16 in. / 40.6 cmRotor5 steel bladesCutting Heights1.1 in. to 2.9 in. / 27 mm to 73 mmHeight Control9-position manual height adjustmentWheel SizeFront: 10 in. / 25 cm; Rear: 6 in. / 15 cmQuad-Wheel DesignYesFoam GripYesFoldable HandleYesTool-Free AdjustmentsYesMulching CapabilityYesRust Resistant DeckYesAssembled Dimensions29.5 in. D x 51.6 in. L x 22.4 in. WNet Weight24.9 lbs / 11.3 kgWarranty2-year limited warrantyWhat's in the BoxIncluded ItemMJ504MReel mower body✔Upper handle✔Middle handle bars✔ 2 includedLower handle✔Handle knobs and bolts✔ 6 includedPaper test strips✔ 20 includedHex wrench✔Manual with registration card✔Before You Mow🚫Keep hands and feet away from the reel and cutting area. Although this mower has no motor, the reel spins when the wheels turn and the blades are sharp enough to cause serious injury.⚠️Clear the lawn first. Remove rocks, wire, toys, sticks, and other objects that could be picked up or thrown by the rotating blades.👟Use safe mowing habits. Wear eye protection and closed-toe footwear. Do not mow barefoot, in sandals, on wet grass, or while running.Assembly🔩Do not fully tighten the knobs until the handle assembly is complete. This makes it easier to align all handle sections before final tightening.1UpperAttach middle bars to upper handle.›2LowerConnect to lower handle.›3Mower BodyAlign lower handle with posts.›4SecurePress inward and tighten.Attach the middle handle barsSecure the two middle handle bars to the upper handle using the first set of knobs and bolts.Connect the lower handleAttach the upper and middle handle assembly to the lower handle using the remaining knobs and bolts.Attach to the mower bodyLine up the holes at the lower end of each handle arm with the short posts on the side plates of the mower base.Lock the handle in placePull both sides of the lower handle bars over the posts on the mower body. Press inward on the handle bars to ensure a secure fit, then tighten all knobs.Cutting Height Adjustment⚠️Set both height levers to the same position. Uneven lever settings can affect cut quality and mower handling.Find the height adjustment leversThe levers are located next to the smaller wheels.Lowest cutting positionPull the adjustment levers on both sides, one at a time, and set them to Position A.Highest cutting positionMove the adjustment levers on both sides to Position B.Choose an in-between heightUse any of the settings between the highest and lowest positions to tailor the cutting height from 1.1 in. to 2.9 in.Ensuring a Clean Cut🚫The steel blades are extremely sharp. Do not touch the blades while checking or adjusting blade alignment. Use caution and wear gloves when working near the cutting area.Place the mower on a flat surfaceRemove the handles and turn the mower reel upside down to expose the cutting bar.Insert a paper test stripPlace a sheet of paper between the blade reel and cutting bar.Turn the wheel by handSlowly turn the wheel. The blades should slice the paper evenly along the entire cutting bar.Adjust if neededIf the mower cuts paper intermittently, adjust the appropriate side of the blades for better cutting performance.Adjusting the Mower Blades⚠️Do not overtighten the adjustment screws. Overtightening can damage the cutting bar. Both screws must be tight during the final adjustment.AdjustmentDirectionMove cutting bar away from bladesTurn adjustment screws counterclockwiseMove cutting bar closer to bladesTurn adjustment screws clockwiseLoosen bladesUse the included hex wrench and turn both adjustment screws equally counterclockwiseTighten bladesTurn both adjustment screws equally clockwiseMowing Tips1Follow the 1/3 ruleDo not remove more than 1/3 of the total grass height in one mowing session, and never remove more than 1 inch at a time.2Mow regularlyMow at least once a week during the growing season to support healthy turf and reduce tall weed issues.3Use incremental cuts for tall grassFor very tall grass, set the mower to the highest cutting height for the first pass, then lower the height for a second or third pass.4Do not force overgrown weedsManual reel mowers can have difficulty cutting tall weeds, such as dandelions, and may bend them instead of cutting them. Cut often to help prevent this.Transporting the Mower🛞During normal use, the blade reel turns whenever the front wheels turn. To move the mower without turning the reel, pivot the handle over the reel and push the mower from the opposite side.Care + Maintenance🚫Keep hands away from the cutting area. If grass clippings are packed near the blades, remove them with a wood or plastic cleaning tool made for blade cleaning.1Keep the mowing area debris-freeRemove rocks, sticks, and other debris before mowing to avoid blade damage.2Lubricate regularlyApply lubricant to the cutting surfaces, cutting reel axle shaft, and wheels for smoother operation.3Keep the cutting bar adjustedCheck blade alignment when cut quality becomes rough, uneven, or difficult to push.4Use light spray oilClean and lubricate the cutting edges regularly with light spray oil.Sharpening the Cutting Blades⚠️Use caution when sharpening. The manual recommends industrial or valve lapping compound between 100 and 240 grit and a light film of wheel bearing grease on the axle and pinion.Apply lapping compoundSpread a thin layer of lapping compound on the front edge of the reel blades.Adjust the cutting barSet the cutting bar so the blade has light but firm contact across the full width of the bar.Turn the reelTurn the reel blades until the front edge of the cutting bar blade is polished.Clean thoroughlyClean all grinding compound and debris from the cutting bar blade, reel blade, pinions, and pawls.Cleaning + Storage1Clean before storingClean the exterior of the mower with a soft brush and cloth. Do not use water, solvents, or polishes.2Clean the blade area safelyTurn the mower on its side and use a wood or plastic cleaning tool to remove compacted grass from the blade area.3Store in a dry placeKeep the mower in a dry storage area and do not place other objects on top of the mower during storage.Troubleshooting GuideUse these quick checks for common MJ504M concerns. Always keep hands and feet away from the reel and cutting area.🌱 Rough or Uneven CutPossible CausesBlade alignment shifted during shipping or useCutting bar is too loose or too tightGrass is too tall for a single passSolutionsUse the paper test strip to check blade alignmentAdjust both screws evenly with the included hex wrenchUse the highest height setting first, then mow again at the desired height💪 Mower Is Hard to PushPossible CausesBlades are adjusted too tightGrass is too tall or wetDebris is caught in the reelSolutionsCheck blade alignment with paper test stripsLoosen the adjustment screws equally if the blades are too tightMow only dry grassRemove debris with a wood or plastic cleaning tool✂️ Paper Test Cuts IntermittentlyPossible CausesCutting bar is not evenly alignedOne side of the blade reel needs adjustmentSolutionsAdjust the appropriate side of the cutting barTurn screws clockwise to move the cutting bar closerTurn screws counterclockwise to move the cutting bar awayRetest with a paper strip after adjustment🌾 Tall Weeds Bend Instead of CutPossible CausesManual reel mowers can struggle with tall weedsGrass or weeds are too overgrownSolutionsMow more often during the growing seasonUse incremental cuts for tall grassFor lawns over 4 inches tall, remove excess height before mowing normally🛞 Reel Turns During TransportPossible CausesMower is being pushed in normal mowing directionFront wheels are turning the reelSolutionsPivot the handle over the reelPush the mower from the opposite side for transport modeVideo GuideFrequently Asked QuestionsWhat is the MJ504M best used for?The MJ504M is best used for small to medium lawns, especially when the grass is maintained regularly during the growing season.Does the MJ504M use gas, oil, or electricity?No. The MJ504M is powered manually by pushing. It does not use gas, oil, charging, or an electric motor.What is the cutting width?The cutting width is 16 inches.How many cutting heights does it have?It has 9 manual height positions, with cutting heights from 1.1 inches to 2.9 inches.How many blades does it have?The MJ504M uses 5 steel RAZOREEL blades.Why is the mower hard to push?The blades may be too tight, the grass may be too tall or wet, or debris may be caught in the reel. Check blade alignment, mow dry grass only, and remove debris safely with a wood or plastic cleaning tool.How do I check if the blades are aligned?Place a paper test strip between the blade reel and cutting bar, then slowly turn the wheel by hand. The blades should slice the paper evenly across the full cutting bar.Can it cut very tall weeds?Manual reel mowers can have difficulty cutting tall weeds and may bend them instead. For best results, mow often and use incremental cuts when grass is tall.How should I clean it?Clean the exterior with a soft brush and cloth. Do not use water, solvents, or polishes. Clean the blade area with a wood or plastic cleaning tool while keeping hands away from the cutting area.What warranty does it have?The MJ504M is backed by a 2-year limited warranty for ordinary household use when purchased from Shop Joe or an authorized seller with proof of purchase. Related articles SPX3500 Electric Pressure Washer