Maintaining a healthy lawn throughout the year can take a lot of effort, especially if you want a lush green lawn. Running into problems such as your lawn mower blade won’t turn can make an already demanding job into a frustrating and sometimes confusing situation. Luckily, there are really only 5 potential reasons why your lawn mower blade won’t turn. So, if you’re trying to figure out how to fix a lawn mower blade that won’t turn, I’ve got you covered.
This article may contain affiliate links, meaning I may get a small commission if you make a purchase through links on this site at no additional cost to you. Visit our affiliate disclosure page to learn more.
Why Your Lawn Mower Blade Won’t Turn
The most common reasons why a lawn mower blade won’t turn is due to a problem with the blade belt, a damaged blade, a seized engine, or debris stuck in the blade housing. With a quick diagnosis, you should find out the cause of the issue and have your lawn mower back up and running fairly easily.
5 Things to Check If Your Lawn Mower Blade Won’t Turn
Here are some common issues you should check if your lawn mower blade won’t turn. In my experience, these 4 issues are typically the cause of the problem.
Blade Belt
Check the blade belt for any signs of damage, wear, or stretching. If it’s loose or broken, it won’t turn the blade.
Pulleys
Check the pulleys to ensure that they spin freely and that there is no side-to-side movement. If the pulley is loose on the spindle, you need to do a repair and potentially replace the pulley.
Blade
Check the blade for any signs of damage, wear, or warping. If the blade is damaged, it can get caught inside the deck and won’t be able to spin properly.
Debris
Check for debris or grass buildup around the blade housing. This can prevent the blade from turning freely.
Engine
Check for debris or grass buildup around the blade housing. This can prevent the blade from turning freely.
How To Fix a Lawn Mower Blade That Won’t Turn (6 Fixes)
Fixing a lawn mower blade that won’t turn can be a pretty easy process. By following the 6 fixes below, you should have your blade working like normal and can get back to working on your yard.
Tightening or Replacing the Blade Belt
If the blade belt is loose or broken, it won’t turn the blade. So, tighten the belt by adjusting the idler pulley or replacing the belt entirely. You can consult your owner’s manual for specific instructions on how to do this. Unfortunately, you need to replace a blade belt that is damaged beyond repair.
Checking the Pulleys
If your lawn mower blade isn’t turning, it could be caused by a problematic pulley. A bad pulley could be anything from a seized pulley to a pulley with collapsed bearings. So, remove your deck belt and take a closer look at the pulley. You might find that you need to replace one of the pulleys. For a more thorough guide, head over to my article on how to test and replace a lawn mower idler pulley.
Replacing The Blade
A damaged or worn-out blade won’t turn properly. So, to replace the blade, first, disconnect the spark plug wire and tip the lawn mower on its side with the air filter up. Then, remove the blade using a socket wrench and possibly a blade removal tool. Install the new blade and make sure it’s secure.
Cleaning the Blade Housing
Debris, such as grass clippings and dirt, can get stuck in the blade housing and cause the blade to jam. To clean the housing, disconnect the spark plug wire and tip the lawn mower on its side with the air filter up. Then, use a brush, scraper, or compressed air to remove any debris. If you are lucky enough, you might have a deck washout feature on your lawn mower, which will do all the hard work for you.
Checking the Engine
If the engine is seized, the blade won’t turn. So, check the oil level and make sure it’s at the recommended level. If the oil is dirty or low, then either top off the oil or carry out an oil change. To learn more, check out my article on how to check the oil in a lawn mower.
If the engine still won’t turn over, I suggest you consult a professional. Unfortunately, a seized engine can’t always be repaired.
Lubricating the Blade Assembly
Lack of lubrication can cause the blade to stick and not turn. Therefore, apply lubricant to the blade assembly, including the blade shaft and bearings. Consult your owner’s manual for recommended lubricants. Typically on larger lawn mowers, you’ll find grease fittings that need regular maintenance. Again, you can find the location of these fittings in your lawn mower manual. Head over to my article on how to grease lawn mower spindles to learn more.
How To Avoid A Lawn Mower Blade That Won’t Turn
A jammed lawn mower blade can not only create a lot of frustration but can also cause some unnecessary wear on your lawn mower. Here are a few tips on how to prevent your lawn mower blade from jamming.
Clear Debris Before Mowing
Before you start up your mower, clear the lawn of any debris, such as sticks, stones, or toys. Any large items can get caught in the blade and stop it from turning. Also, keep an eye out for debris as you mow, and stop the mower to remove it if necessary.
Mow in Dry Conditions
Wet grass clumps together and tends to stick in the blade housing. Unfortunately, these clumps can jam up the blade and stop it from spinning, as well as create other headaches like clogging up your mower’s bagger chute. To avoid this, mow when the grass is dry.
Don’t Scalp the Lawn
Cutting the grass too short can cause stress on the blades and lead to blade jams. Make sure to adjust the height of your mower deck to the recommended level for your grass type. Head over to my article on 6 tips for setting the right lawn mower cutting height to learn more.
Keep the Blade Sharp
A dull blade can tear the grass rather than cut it cleanly, causing clumps of grass to build up and jam the blade. So, regularly sharpen the blade to the correct angle or replace it when it becomes damaged. Visit my articles on when to sharpen lawn mower blades and how to sharpen your lawn mower blade using three common methods.
Keep Up With Regular Maintenance
Regular maintenance can help prevent blade jams. Therefore, check the blade belt for wear, keep proper tension on the belt, and keep the top of the cutting deck (belt driver blades) free of debris. Check out my article on how to use belt dressing and conditioner for lawn mowers to enhance the performance and extend the lifespan of your belt.
