Can I Hose Down A Lawn Mower?

If you want your lawn mower to cut grass cleanly, you need to sharpen the blade regularly, but that's not enough. You also need to clean the undercarriage because grass that collects there interferes with the blade, making it spin more slowly and rip grass rather than lopping off the tops. Besides that, accumulated grass promotes rust, inhibits airflow, and affects engine performance. If it seems to you that washing off the grass is easier and does a better job than scraping, you're not wrong, but you have to do it properly to avoid damaging your mower. 

Some mowers have a washing port that allows you to attach a hose and wash the undercarriage while the motor is running and the blades are spinning. This is a great cleaning option that has been available since the 1990s. It's more common on riding mowers than on push mowers, though, and that's because push mowers don't really need it; it's easy to tip one on its side to wash it. 

You can use a garden hose or a pressure washer to clean your lawn mower, but if you use a pressure washer, keep the pressure moderate (between 2,000 and 3,000 psi), and use a nozzle with a fairly wide spray pattern (25 degrees is ideal). Make sure no water gets into the engine, fuel tank, or — if you have a cordless model — on the battery. Thoroughly dry the mower before turning it upright to help prevent rust and component damage.

Before you wash your lawn mower, it's important to disable it to prevent an accidental start. If you have a gas-powered mower, remove the spark plug wire and tape it out of the way, but leave the plug in place, because removing it would allow water into the combustion chamber. If you have a cordless model, remove the battery. It's a good idea to run the fuel tank on your gas mower low before cleaning, but if you don't, make sure the side with the air filter is facing up when you tip the mower to prevent oil from flowing into the air filter or carburetor.

With the underside of the mower exposed, you can hose it down to get grass off the mower deck and the blade. A scraper or putty knife can help you remove what won't come off with water. Don't point the nozzle directly at the blade shaft, especially if you're using a power washer, because you don't want water to leak through to the engine. When all the grass is gone, get the surfaces you washed as dry as you can, using a rag, then turn the mower upright and let it sit for an hour or so to let air finish the job. 

If you want the next cleaning to go faster, spray vegetable oil — a cheap kitchen staple — or WD-40 on the underside of the deck and blade after they have dried. Both of these will prevent grass from sticking.