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

Blade and deck problems are usually maintenance problems, and two habits prevent most of them: never remove the blade guard to clean underneath, and never point a pressure washer at the deck. The rest is owner practice — rotation patterns, preloaded disc sets, skid guards, and contact cleaning.

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.

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. Instead, pressing the grass-height button 2-3 times lowers the blade disc all the way down, giving cleaning access without removing the guard².

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.