Replace mower blade

This video walks you through the whole process step by step, including: blade and blade boss inspection, bolt removal, fitting new blade and torqueing blade bolt to specification.

Over View

You’ll find useful resources on this page, tips, links to tools, parts and supplies required to complete your repair.

An old blade will cause a ton of problems, including:

  • Engine vibration, which can lead to a list of more serious issues.
  • Lawn damage, old blades tear the grass instead of cutting clean, torn grass leads to excessive moisture loss and yellowing of the lawn.
  • Clogged grass chute, the worn blade wings no longer creates enough force to lift the grass or to move it to the bag. This results is persistent and annoying clogging and clumping on the lawn.

This video covers the removal and replacement of the blade, the easy way.

Before working on your mower be sure to remove the plug wire to prevent accidental starting, see “Repair Safety Video”.

Tools & Parts

To nail this procedure you may need the following tools, parts and supplies.


WD40

This is the first tool on the list for good reason, WD solves a ton of problems. I won't work without it, because I can't. Picture links to Amazon.com

Ratchet Tool Set

Before we can do anything, we'll need tools. I've selected this set as I own some Craftsman tools and while I have worn some out, they did do a lot of work. So I expect this set will last the occasional user quite a long time.

This set carries both metric and standard sockets and that's important, because some mowers will have both type of fastener sizes. Set includes spark plug sockets. Picture links to Amazon.com


Gas Line Clamp

Some small engines will have a gas tap, which is really handy when removing the carburetor, stops gas flowing all over the shop. However most engines won't have one, these useful clamps simply squeeze the fuel line and prevent a spill while you perform surgery. Picture links to Amazon.com

Impact Wrench

I love DeWalt, they're make quality tools. This heavy duty but lightweight 1/2 inch impact wrench makes short work of stubborn bolts like flywheel nuts and rusty blade fasteners. Upto 700 ft lbs of torque on tap, I keep one in the trunk of our family car, makes a flat almost enjoyable. Picture links to Amazon.com

Drill/Screw Gun

I use a Dewalt screw gun (also a drill) in the workshop to speed up the process of removing engine covers, carburetor bolts, Armature bolts etc. It's a brushless motor and as tough as nails, I driven over it a few times - still works great! Batteries are interchangeable and so if you have a Dewalt product already you won't need the battery. Picture links to Amazon.com

Torque Wrench

Teng 1/2 Torque wrench, fantastic tool I use it every day and mine is still going strong. A torque wrench is advised for tightening components such as flywheel nuts and blades. The torque spec of these components is very important. Picture links to Amazon.com

If you are considering buying a torque wrench, definitely check out my review of Teng torque wrench.


Blade sharpening tool

Handy blade sharpening kit that fits to a cordless drill, includes blade balance tool. Picture links to Amazon.com

Blade holding tool

Very useful blade holding tool, used to hold the blade steady while the blade bolt is loosened and tightened. Picture links to Amazon.com

Wire brush kit

Stainless for heavy duty and brass for and brass wire brush kit for heavy duty and finer applications like electrical connections and softer metals. Picture links to Amazon.com

Wire wheel

Wire wheel and drill makes life easy and the job almost enjoyable! Picture links to Amazon.com
Auto Technician and Writer at | Website

John Cunningham is an Automotive Technician and writer on Lawnmowerfixed.com. I've been a mechanic for over twenty years, I use my knowledge and experience to write "How to" articles that help fellow gear-heads with all aspects of mechanical repairs, from lawn mowers to classic cars.