Why your mower starts then stalls

The most common symptom of an ailing lawn mower is that it won't start at all or roars to life, runs for a few seconds, and then stops dead. If you ran your mower dry of gas at the end of the season, as recommended, there are a few other things you can check before giving up and taking the mower to a repair shop. Here are things to try that cost little or nothing:

A spritz of carb cleaner

Mower carburetors have a bowl at the bottom that holds fuel prior to burning. At the bottom is a bolt you can remove to drain the last drops of fuel after running the mower dry at the end of the season. (Unfortunately, the design of some newer mowers inhibits easy access to the bowl.) With certain mowers the bolt has tiny fuel-metering holes at the point or along the threading that must be kept clear—or the mower will repeatedly stall after starting.

To access the bolt with fuel in the tank, use a clamp to choke off the flow. Once the bolt is off, remove the bowl (some fuel will spill out even with clamping) and clean it. You can use a small wire to clear the bolt's holes, but a few good sprays of carburetor cleaner should suffice. Replace the bowl, retighten the bolt and, of course, remove the clamp before restarting.

Other possible causes

If the bowl of your mower is inaccessible, check the spark plug. An old or improperly gapped spark plug can make for difficult starting. So can a heavily clogged air filter. But if you've recently replaced both, the carburetor cleaner can be put to another use. Remove the air filter, and find the intake port—through which filtered air enters the carburetor. Spray carb cleaner into the intake. With the filter still off, try to start the mower. You might need to repeat the spray-and-start a few times. Once the mower starts and stays on, you can replace the air filter and housing. If the mower stalls once you've reinstalled the filter, examine the filter more closely for any soaked-in oil. When in doubt, replace it.

Need a new mower?

Sometimes a mower is beyond repair even by a pro—at least at a price you're willing to pay compared to the cost of a newer one. If that describes your situation, check Consumer Reports' lawn mower buying guide, which compares features and capabilities of today's walk-behind mowers, lawn tractors, zero-turn-radius riders, and rear-engine riders. Then view our lawn mower Ratings of more than 180 models. Top-scoring self-propelled mowers, best for most lawn, include the $500 Honda HRR2169VLA, $520 Toro Super Recycler 20381, and $330 Troy-Bilt TB-320 12AVC35U.

—Ed Perratore (@EdPerratore on Twitter)