Replace Primer Bulb Video

Starting your mower without a functioning primer bulb is difficult, and especially so as the summer fades and days turn cooler.

This video covers primer bulb replacing, a common cause of hard cold starts.

Over View

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

Primer bulbs have an important function, they add extra gas to the engine in preparation for a smooth start. Without the extra gas the engine likely won’t start, or starts and stumbles.

Primer bulbs get a ton of use and as they’re made from rubber perish over time. Luckily replacing the primer bulb is easy and you won’t even need to remove any components, it’s all covered in this video.

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.


Briggs & stratton

This is a common Briggs air filter housing with integrated primer bulb. This kit includes the housing, gasket and primer bulb. Very often the fault isn't with the primer bulb itself but instead a faulty housing or gasket. Picture links to Amazon.com

Briggs & Stratton

Pretty common style Briggs primer bulb with keeper ring. Amazing how something so simple can make such a difference. Picture links to Amazon.com

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 & Oil Syphon

You'll find this tool really useful if you need to drain the gas tank, and you will if the gas is stale. The siphon will remove it without fuss or mess and it can be used for extracting the oil too. 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

Carb Cleaner

When cleaning your carburetor you'll need this stuff. Gumming is a sticky substance that's hard to shift. The carb cleaner will remove it, however if your carb is really bad, save yourself some work, go ahead and buy a new carburetor. Picture links to Amazon.com

Cleaners

You'll find these nylon brushes super useful when it comes time to clean those tiny passageways of the carburetor and jet. Use these in conjunction with the WD Carb cleaner. 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
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.