Blade & deck maintenance: what owners do, and what Mammotion warns against

Related: the mechanical-causes checklist for symptoms that are mechanical rather than firmware, and the loud or grinding deck-noise report if the deck is making a noise rather than needing service.

Extending blade life on dual-disk models. A LUBA 1 owner's 4-year rotation pattern¹: install new blades on both disks; at the next scheduled change, swap the left and right disks with each other (uses the unworn edge without removing anything); at the following change, remove the blades and flip each one to its other edge; at the next change, swap disks again; repeat. Always remove the cutting disks before removing or installing blades: pushing down on blade screws while the disk is still attached to the mower risks bending or loosening the motor shaft. If reusing screws rather than fitting new ones, use blue or purple threadlocker. Bare screws have been reported backing out and losing blades entirely. Also check for an in-app Blade Replacement Reminder (Device Information → Maintenance) if your model has one (not available on LUBA 1, per the reporting owner).

Faster blade changes: keep a spare set of cutting discs preloaded. Two owners in the same thread independently keep a second set of discs with fresh blades already fitted¹. One notes it "ends up being 6 screws instead of 12," the other that switching to a preloaded pair "makes replacement far more ergonomic" and that the discs are cheap enough to be worth it. The blade-screw work then happens on a bench rather than while kneeling at the mower, and the mower is off the lawn for less time. Read it as a practical maintenance habit from two owners, not a manufacturer instruction.

Non-original blades. Two owners of a LUBA mini 2 thread about blade life report trouble after fitting blades that were not Mammotion's. One had a couple of them break, leaving fragments about 2 cm long on the lawn¹¹. Another has found the mower pretty loud ever since changing to non-original blades, and asks whether that could be the cause¹². Neither confirms a cause. Another owner says a strong magnet fixed to the mower collects fragments on the next run, which is worth knowing if a blade does break¹¹. When blades are very dirty, one owner soaks them overnight with a dishwasher tablet¹³.

A mower that suddenly vibrates or gets loud. A LUBA 2 owner whose mower shook had only two screws in one cutting disc, because a thread in the other was damaged. Another owner says vibration will shut a mower down if blades, blade-mounting screws or disc screws are missing, or if the blade-motor spindle nut is loose¹⁷. A Mammotion staff account in the thread told the owner to take both discs off, start the blade motor from the app to hear whether it runs normally, tighten the nut, and refit the discs with no screw loose¹⁸. The owner fitted new nuts and discs and says it still shook, so treat this as a checklist, not a fix¹⁷. A disc that rattles, stops after a few seconds or spins more freely than the other is a related case. Mammotion's Mammotion-Luna account asked an owner in that position to take the discs off, check the blade disc adapter nuts are tight, test the mower without the discs to see if the rattle stops, and then refit them with all three screws on each disc tight²¹. Two owners in the thread say to look for grass or other material wrapped round the motor shaft under the disc, and dig it out²²²³. A commenter says a freely spinning disc is often a sign of a burned-out motor, which is that commenter's reading²⁴. A YUKA 2000 owner whose mower got loud after a blade went missing fitted one from another maker; the same account said that running two different types of blades together may cause this, and the owner says the noise fell by about half and did not go away¹⁹.

Two owners say lifting the shell off and refitting it cleared a deck-height error. In a thread about a deep clean, a LUBA 2 owner says that removing the shell and putting it back corrects the deck motor height errors without any other change, and the owner who started the thread agrees and cannot say why it works²⁰. The warning above applies: Mammotion has said that taking the device apart yourself may cost the warranty⁶, so this is what two owners did, not something to do first.

Power the mower off and take the key out before you reach underneath. Mammotion's own account tells owners to fully power off the mower and remove the safety key before cleaning the underside¹⁴, and its fall-care post says the same, adding that you should wear gloves and check the cutting disc and blades for grass and debris¹⁵. The key does not do the same thing on every model. On a LUBA 2, one owner says it is only a jumper that disables the cutting motors while the rest of the mower stays live, and that holding the power button until the beep is what shuts the mower down completely¹⁶. Your manual says what the key does on your model.

Lower the disc the way your model does it. To reach the underside, bring the cutting disc down first. On a LUBA the cutting height is set in the app⁷ (one LUBA mini owner simply presses the height button two or three times²). On a YUKA, YUKA mini or YUKA mini 2 there is no app setting: you press down and turn the cutting-height knob on top of the mower^{8 9}.

Don't remove the blade guard to clean underneath it. Mammotion's own manual explicitly warns against demounting the blade guard ("Schutzbügel") to clean the underside: doing so releases the height-adjustment bellows underneath and risks water getting in². On at least one 2025-model unit, the guard's retaining screws were found intentionally sealed shut, which two owners speculated is a tamper-detection measure tied to warranty coverage². Mammotion has since said the warranty link out loud: replying to a LUBA 2 owner who had taken the deck apart for a deep clean, its official Reddit account wrote that "disassembling the device by yourself (especially without professional operation and forcefully disassembling) may result in the loss of the equipment's warranty rights", and asked owners to contact support first when something fails⁶. Instead, pressing the grass-height button 2-3 times lowers the blade disc all the way down, giving cleaning access without removing the guard².

What some owners did instead, and why it is not a fix. Two owners, one of them on a LUBA 3, cleared a "Cutting Disk Blocked" error that a surface clean had not fixed only by removing the guards around the blade motors and clearing grass packed in by mowing in wet conditions, the step the warning above advises against¹⁰. Mammotion's reply in the same thread asks owners to clean the cutting-disc area and contact support if the error persists¹⁰. It is reported here so you know what owners have tried, not as a recommendation: taking the mower apart can cost the warranty⁶, so if cleaning without removing the guard does not clear the error, the next step is Mammotion support.

Don't clean the underside with a hose or pressure sprayer. One owner used a cleaning-syringe/jet sprayer on the underside for a few seconds and the mower never powered on again. Mammotion's own body wasn't sealed to the level its marketed water resistance implied⁴. Forum members point out the nuance: "resistant to strong jet water" (roughly IPX6) is not the same as submersion-safe, and a mower's actual sealed compartment is around the electronics in the body, not the leg bellows/joints. Treat any pressurized water source as off-limits and wipe the underside down instead. Mammotion never responded to this owner's support requests about the failure.

Charging contacts corroded/charring with no obvious cause. One owner traced a repeatedly-failing charge to a slug that had bridged the charging contacts and gotten charred there; lightly sanding the contacts clean restored normal charging³. Worth checking for debris/pests before assuming a dock or PSU fault, especially if a contact looks physically discolored.

Why these mowers can leave cuttings looking different from a traditional push mower, even when working correctly. A push or riding mower's spinning blade creates airflow that lifts grass upright before cutting and often bags/discharges the clippings. Robot mowers don't generate that lift: the blade disc simply passes over grass at whatever height it's standing, with no fan effect, and clippings are left in place rather than collected⁵. Practical implication: because there's no lift to help the blade reach leaning or matted grass, mowing more frequently (rather than less) compensates for the lack of a traditional mower's airflow advantage. Letting grass grow tall between sessions makes each pass less effective, not just slower.