Q&A: Why won't my mulching mower mulch?

My 2-year-old mower doesn't seem to be doing its usual good job of mulching grass clippings. The machine is otherwise working well—I had a professional mower tune-up at the beginning of the season and the blade sharpened. What could be wrong?—J. Rubinstein, via e-mail

My initial guess would have been a dull blade, but since you had it honed recently, that's not the likely cause of poor mulching.

Your next step is to clean the bottom of the mower deck—the area where the blade spins around. It's quite common for clippings and dirt to accumulate here, especially if you've recently cut thick and/or damp grass. Built-up clippings will prevent your mower from mulching properly by impeding the recutting action of the blades.

Here's what to do:

• Turn your mower on its side with the carburetor and air filter facing upward to eliminate lubrication oil from getting into the fuel system.
• Loosen the gunked-up mess with a water hose, then remove it with a scraper.
• After cleaning, spray silicone lubricant, like the 3-IN-ONE Professional Line silicone spray from the maker of WD-40, on the inside of the deck to keep clippings from building up.
• I also suggest you clean off the clippings at the end of each mowing—they're much easier to remove then.—Peter Sawchuk, Consumer Reports mower expert

Essential information: For more advice on how to keep your mower in tiptop shape, check out "Midsummer mower maintenance."  And if your mower or tractor needs to be put out to pasture, read our May 2007 report on mowers and tractors, and use our free advice on choosing the right mower, tractor, or zero-turn-radius machine.

Send your questions about the yard and garden or any other home-related topic to our experts.

Comments

[Ted]

Shouldnt step 1 be "pull the spark plug wire off of the plug"?
(Something my daddy and other mechanics always told me to do, but then again, that may not apply to new equipment).

[phil kryder]

Hey, thanks for updating the blog to remove the implication that WD-40 is a silicone lubricant!