Lawn mowers rely on their blades as the component that actually does the cutting. If the blades do not engage, the situation will be extremely troublesome.
There are a number of potential reasons why your mower’s blades won’t engage, including a broken deck belt, a faulty PTO switch or clutch, dull or improperly mounted blades, a dead internal battery, or a drained fuel tank.
Continue reading to learn why lawn mower blades won’t engage and how to resolve this frustrating issue.
How Do The Lawnmower’s Blades Function?
The primary function of a lawn mower is to cut grass by rotating a blade. But it isn’t as easy as it seems.
Because grass is so light, it moves when you drag something through it. Your lawnmower must perform a certain way to cut.
However, have you ever checked your lawnmower’s blade? It’s not completely straight. Lift and suction come from the blade’s end tabs.
Because of this movement and the confined nature of the mower deck, the grass gets sucked up as the mower moves over it. This causes the grass to stand upright as the blade moves through it.
To operate the mower blades, a pulley assembly must be manually engaged by shifting a lever, which then tightens the blade driving belt. The pulleys will be spun by the belt, which will be driven by the engine’s rotating shaft, and the blades will be cut at high speed.
Check this video to know how the blades actually works!
Lawn Mower Blades Won’t Engage: 6 Ways to Fix
Your lawn mowers blades may not engage for many reasons.
Here is a quick table of possible causes and simple solutions for lawn mower blades not engaging.
|Stretched or loose belt||Replace the belt|
|Faulty PTO clutch||Install a new clutch|
|Defective PTO switch||Replace the faulty switch|
|Dull/ Bent blades||Sharpen/replace the blades|
|Weak internal battery||Charge/ install new battery|
|Faulty blade engagement cable||Remove the faulty cable|
Stretched 0r Loose Belt
One of the most common reasons your blades won’t engage is a belt that is too loose or too stretched and keeps slipping off. The belt will eventually wear out and require replacement.
The belt might have twisted as well. Too much grass or leaves being processed at once may cause a buildup under the deck, which in turn may force off the belt.
Wear and cracks should be checked at least once a year on the belt. If the belt breaks completely, the engine will run but the blades won’t.
- Remove the belt cover first.
- Once the belt is exposed, twist it around the pulleys and remove it.
- If there are multiple blades, there will be an idler pulley. When removing the belt, record its route around the pulleys.
Faulty PTO Clutch
To disengage the engine from the blades, you can use the PTO (Power Take Off) clutch. To power the lawnmower’s blade rotation, the clutch solenoid must be activated to contact the drive belt.
There will be no engagement of the lawnmower blades if the PTO clutch is not receiving power, the clutch solenoid is broken, or the clutch itself is worn out.
- The first thing to do is get to the clutch and check it out. It is located on the mower’s bottom, above the blade.
- Remove the cover to have access to the clutch.
- • Look for metal shavings, powder, excessively loose or misaligned parts, and damaged or missing springs.
- Fix the problem by swapping out the damaged or worn parts.
Defective PTO Switch
To engage the PTO clutch, the PTO switch must be turned on. The PTO clutch may be left without power if the switch were faulty. Lawnmower blades won’t spin because the clutch won’t engage.
- To start, use a multimeter to check for continuity to see if the switch is broken.
- Switch out the PTO if it’s broken.
Dull/ Bent Blades
If you haven’t been keeping up with regular sharpening and servicing of your lawn mower, the blade may eventually become dull or curved, and you’ll end up with inconsistent cuts or rows of uncut grass.
- The blades of a lawn mower must be sharpened or scheduled for maintenance.
- A loose blade could cause problems, so it’s important to keep it in place.
Weak Internal Battery
When the internal battery of your lawn mower is dead, not charged, or underpowered, the blade will not engage.
Battery life should be checked if turning on the device does not start the blades. The lawn mower’s battery needs to be charged to full capacity, and if it’s defective, a new battery should be installed.
Faulty Blade Engagement Cable
If your lawnmower blade won’t engage, the cable may be broken. Blade bail and blade clutch are connected by the blade engagement cable. Metal cables cause most blade engagement cable issues.
Years of use can break the cast ends that link the cable to the bail and clutch. Rust causes steel cable fraying and breakage.
- Start by removing attachment mounting and cutting cable ties that hold the cord to the mower handle.
- Then, thread the cast end of the cable out of the bail hole to remove it. Remove the blade clutch’s opposite cable end.
- To access the clutch, you need to remove a mower cover or two.
- After accessing the clutch and cable, remove the cast cable end from the clutch.
- Insert the cable backwards. Replace blade clutch covers. New cable ties attach the cord to the handle. Adjust the cable to finish.
Frequently Asked Questions (FAQs)
How should I sharpen my lawnmower blades?
Using a bench grinder is the quickest method for restoring a dull lawn mower blade. Using safety glasses, earplugs, and gloves, grind the blade edge against the rotating wheel.
Why doesn’t my lawnmower’s blade engage?
The failure to engage the blade could be due to the clutch, PTO, or belt.
Are the blades engaged by the PTO?
When the PTO switch is activated, the blades do not engage.
Why my mower dies when I engage the blades?
If the belt isn’t positioned properly, the engine could die as soon as the blades are turned.
Can you use any blade on a lawn mower?
Lawnmower blades are mower-specific and not universal.