Briggs & Stratton (Classic) surging

This video walks you through the repair of a very common B&S (Classic/Sprint/Quattro engine) surging cause.

A bad spark plug can be the route of many problems, be sure to check the plug before performing carburetor work.


Classic manifold replacement

This video covers the replacement of the B&S (Classic/Sprint/Quattro engine) manifold. It's another common cause of irritating engine surge.

Briggs & Stratton (Intek) surging

This video covers the repair of a surging Briggs & Stratton Intek engine.

A bad spark plug can be the route of many problems, be sure to check the plug before performing carburetor work.


Briggs & Stratton (E Series) surging

This video covers the complete surging repair of the Briggs and Stratton E series engine. It's one of Briggs latest engines and fitted to many mowers. The carburetor is plastic and causes some very common surging issues.

A bad spark plug can be the route of many problems, be sure to check the plug before performing carburetor work.


Kohler surging

This video covers the complete repair of a surging Kohler engine. Kohler engine are easy to work on and in many cases just a few minutes work solves the problem.

A bad spark plug can be the route of many problems, be sure to check the plug before performing carburetor work.

Over View

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

All mowers suffer from carburetor problems and surging or erratic idle is a common symptom.

However, other causes of surging should be eliminated before cleaning the carburetor. Go ahead and drain the carb bowl, remove, clean and gap or replace the spark plug, check if the gas is fresh, is air filter OK?.

Having eliminated these, it’s time to clean the carburetor idle jet. Many mowers will allow easy access to the idle jet, and for others we’ll need to remove the carburetor. 

Surging or erratic idle may also be caused by a faulty carb, or vacuum leak caused by bad carb gaskets or manifold.

This video shows the complete job start to finish for many common engine types. 

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 first 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

Gas Stabilizer

Mix this with the gas when winterizing your small engine. Gas isn't what it used to be, it goes stale, in some cases after just one month. Bad gas causes gumming and that's a carburetor killer. Stabilizer will save you money and stress in the long run. Picture links to Amazon.com

Gas Can

Briggs and Stratton refuel can. These guys got it right, I like it a lot, it offers press button control, no fuss no mess and no funnel required. Picture links to Amazon.com

Briggs & Stratton

This is a popular Hooai Carburetor fitted to walk behind mowers with Quantum engines, but check the engine codes listed. This is an Auto choke carburetor.

This carburetor has a fuel feed bolt in the base of the bowl, dirt in the bolt feed hole is a common issue. Picture links to Amazon.com

Briggs & Stratton

This is a after market replacement carburetor for the Briggs 4-7hp engines. This is the primer bulb style carburetor.

This carburetor has a fuel feed bolt in the base of the bowl, dirt in the bolt feed hole is a common issue.

It comes with a replacement air filter/primer bulb housing gasket. Without this gasket your primer bulb won't work. Picture links to Amazon.com

Briggs & Stratton

This is an original Briggs carburetor fitted to walk behind mowers. Part # 593261, these guy's are made from plastic and I see lots of issues with them. The jet holes are particularly tiny and block so easily. There are a few different types and all look alike, so use part numbers to check before ordering. Picture links to Amazon.com

Briggs & Stratton

This is a popular carburetor fitted to the classic range of Briggs and Stratton engines. This engine is fitted to many different walk behind lawn mower mower models like, MTD, TORO, Murray, Poulan, Craftsman and many more. 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
John Cunningham
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.