Rust is a common problem with lawnmower decks simply because moisture is trapped in the underside of the mower during use. The mower deck is an important component as it keeps the blades protected and helps to prevent accidental user injury. Maintenance after each use is the best way to keep the mower deck in top shape. This type of routine maintenance takes little time and no special tools are necessary to keep your lawnmower deck from rusting.
Raise the mower deck to its highest level.
Drive or push the lawnmower onto a ramp, allowing the front wheels to be up higher than the back wheels. Secure the mover to prevent it from moving backward.
Find the spark plug wire and disconnect it.
Use a garden hose on a high-pressure setting to spray the underside of the lawnmower deck. Any debris or clumps of grass will come loose.
Spray the entire lawnmower with water to fully clean it. Allow it to air dry.
Locate the spark plug wire and reconnect it.
Store your lawnmower in an area where it can drain properly while drying.
You can wipe the lawnmower down using a towel; do so with caution.
Do not flip the lawn mover over and attempt to spray the underside of the deck.