In this edition of Maintenance Monday, we’re answering a question from Brenda in North Carolina. The engine of her five-year old lawn tractor runs fine, but the mower won’t engage. Why?
Gary Oshel is a product support representative with John Deere. He says the first thing to do is make sure there is a belt on the mower deck. If it’s there, the problem is either mechanical or electrical. Start by checking the PTO.
“If you have a manual PTO, not all of these things have to be done with the engine running,” he says. “If you know the engine runs, you can turn that off and start flipping up your manual PTO switch and seeing if it moves freely, or if there’s some tension there. If it moves freely, it’s the linkages between your PTO switch and your clutch, or your belt.”
If the PTO is electrical, you should hear the PTO clutch click when you flip the switch. If you don’t, check the battery. A low charge may not provide enough juice to engage the PTO. If you do hear the click, there is power going to it.
There could be a problem with safety switches. On most newer model lawn mowers, the brake has to be disengaged or off for the blades to operate. You also have to be sitting on the seat to engage the PTO, so the seat switch may be malfunctioning. If the safety switches check out okay, Oshel says the next step is to inspect the mower deck itself.
“Shut the engine off and if it’s a manual PTO, make sure your deck engagement spring is connected correctly and if it’s an electric PTO, again, check the belt. It could be your bearings and your spindle pockets, or spindles, have seized up,” says Oshel.
If the blades are stuck, pump some grease into the fitting and carefully work the blades back and forth by hand until they move freely.