How to Repair Small Engines
- Fuel and Exhaust. The fuel and exhaust systems are critical to operation. They furnish the fuel for combustion and remove exhaust gases.
- Ignition. The ignition is a primary system within all small gas engines. It produces and delivers the high-voltage spark that ignites the fuel-air mixture to cause combustion.
- Combustion. The combustion system of a small gas engine is where the work gets done. ...
Full Answer
What is the best way to learn small engine repair?
- Formal Training. While many small engine repairers enter the field with a high school education and receive on-the-job training, you can also complete a small engine training program to prepare ...
- On-The-Job Training. ...
- Employment Outlook. ...
What tools are needed for small engine repair?
- The lawn mower’s motion and engine vibrations can cause such hardware as the fasteners and wheels to loosen. ...
- If you have an electric mower, be sure to inspect the cord or battery to make sure they remain in good condition.
- Store the battery or cords in a dry location.
How to diagnose and repair a small engine?
Before you dive too deep into your engine, check the basics:
- Is the tank filled with fresh gas?
- Are all safety devices/switches disengaged?
- Are you using proper starting procedures?
- Is the spark plug dry/wet?
- Is the equipment tuned-up?
- Is there smoke?
How to rebuild a small engine?
How to Repair Small Engines: Cleaning the Carburetor
- Don't Google "small engine repair near me" the next time your lawnmower sputters. ...
- Introduction. ...
- Tools Required
- Materials Required. ...
- Start Your Engine (At Least Try) Confirm that the fuel valve is on, there's gas in the tank and the spark plug is in good shape. ...
- Test for Gas at the Carburetor. ...
- Remove the Carburetor. ...
- Check for Corrosion. ...

What is the most common problem with small engines?
Carburetor. Most of the common problems with small engines point to fuels. However, if the carburetor fails to mix the fuel and air properly, engines malfunction. If a carburetor becomes dirty, it clogs easily which keeps it from functioning well.
How do you make a small engine run again?
3:4610:42Tips on Starting Small Engines that Haven't Ran for a While - YouTubeYouTubeStart of suggested clipEnd of suggested clipPull your spark plugs out ground it out and crank it over and watch for spark when the plug. AndMorePull your spark plugs out ground it out and crank it over and watch for spark when the plug. And this one you're going to do that on both sides. If you got spark. You might have a stuck valve.
How do you fix a small engine that won't start?
6 Tips for Troubleshooting a Small Engine that won't StartInspect the spark plug. One of the first things to check if your small engine won't start is the spark plug. ... Check your fuel. ... Clean the carburetor. ... Take a look at the compression system and the valves. ... Check the start switch.
What tools do you need to rebuild a small engine?
0:4719:35Small Engine Repair - Basic Tools - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd they also include some allen tools in here as well as like a pair of pliers. And just someMoreAnd they also include some allen tools in here as well as like a pair of pliers. And just some various stuff you will also have two spark plug sockets that are most common.
Can wd40 be used to start engines?
0:001:05will WD 40 work instead of starting fluid? - YouTubeYouTubeStart of suggested clipEnd of suggested clipProblem once the wd-40 burns out of the carb the engine stops the wd-40 doesn't burn as clean as theMoreProblem once the wd-40 burns out of the carb the engine stops the wd-40 doesn't burn as clean as the fuel or the starting fluid.
How do you start an engine that has been sitting for years?
4:4011:27How to Start a Car That's Been Sitting for Years - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd you want to look at the area that's in the engine. And sparks you want to make sure it's notMoreAnd you want to look at the area that's in the engine. And sparks you want to make sure it's not gummed up with oil if it is clean it off or replace them.
How do I fix my lawn mower engine?
0:002:28Lawn Mower Repair : How Do I Repair a Lawnmower Engine? - YouTubeYouTubeStart of suggested clipEnd of suggested clipIt will lead to a follow spark plug poor. Performance. So we'll just remove the air filter and oneMoreIt will lead to a follow spark plug poor. Performance. So we'll just remove the air filter and one way to check it besides the obvious of seeing if it's dirty is you remove the outer layer.
What can be used as starting fluid?
Starting Fluid Substitutes As discussed you can use carby (carburetor) spray as an alternative to starting fluid. We do recommend specific engine starting spray when available as the pressure is lower and the nozzle on the can creates more of a mist.
How do you know if a small engine has spark?
1:085:28HOW-TO Check For Spark Plug Fire On A Small Engine - YouTubeYouTubeStart of suggested clipEnd of suggested clipIf it's really weak your engine may not start. Now. If your equipment won't start and you have goodMoreIf it's really weak your engine may not start. Now. If your equipment won't start and you have good spark you can eliminate the fact that it's not spark causing you the no start problem.
How much does it cost to rebuild a small engine?
between $2,500 and $4,000A typical engine rebuild is between $2,500 and $4,000 in parts and labor costs. This type of engine repair might include simply replacing bearings and seals, and obviously taking the engine out and re-installing it. It could be much higher too.
Is it worth rebuilding a lawn mower engine?
If the equipment the engine powers is old, it may make sense just to buy a new lawn mower, log splitter, or whatever machine is in question rather than spend money diagnosing and fixing its engine. If it's a newer piece of equipment, it could be worth repairing or replacing the engine, depending on the diagnosis.
Do you need special tools to rebuild an engine?
Besides the basic metric wrenches and socket sets you will need many other tools, including: Air compressor. Engine assembly lube. Basic set of hand tools.
How much does it cost to service a lawn mower?
The cost of a lawn mower repair will vary depending on many factors, including complexity, time and materials required for the project. But you cou...
Is small engine repair profitable?
Small engine repair could potentially be profitable if you have a high volume of repairs.
What is considered a small engine?
A small engine is the term that includes a variety of low-powered internal combustion engines, including those to power lawn mowers, generators, le...
What is considered small engine repair?
Small engine repairs include routine tuning and maintenance of equipment, including lubricating parts, replacing plugs, etc.
How to remove carburetor from engine?
Remove the Carburetor. Use a socket or nut driver to remove the two bolts that hold the carburetor to the engine. Unhook the throttle cable from the carburetor linkage. Place the carburetor in a container (to catch the gas). Step 4.
How long does it take to fix a lawn mower carburetor?
Solve most lawnmower or other small engine starting problems with a simple diagnosis and a carburetor cleaning or rebuilding. It will only take a few hours, and you'll avoid the minimum $70-plus-parts repair bill.
How to clean a carburetor?
Clean the Parts. Wire all the larger parts together and drop them into a bucket of carburetor cleaner. Wrap the small parts in a piece of aluminum screen or use a fine-mesh basket, and drop them in the bucket as well. Note: New/replacement parts don't need to be cleaned. Let the parts soak for one hour.
How to clean a carburetor with aerosol lubricant?
Shoot a one-second burst of aerosol lubricant or carburetor cleaner down the throat of the carburetor.
How to get a spring clamp back on a fuel line?
Compress the spring clamp and slide it backward on the fuel line.
Can you rebuild a carburetor?
If there's no corrosion in the carburetor, you can choose to rebuild it rather than replace it. But rebuilding isn't always cheaper, and it might not even do the trick. Sometimes you can buy a new carburetor for less than (or pretty darn close to) the cost of the rebuilding kit plus the cost of the chemicals. We always just replace bad carburetors rather than rebuild them.
Getting Started
For those new to small engine repair, the best resource is the manual. The level of detail should solve most issues with your small engine. Next, check out the abundant resources on the Briggs & Stratton website, complete with frequently asked questions, and videos to help.
Buy the Right Repair Parts
Be sure to buy Briggs & Stratton genuine parts that can be found on our online store or at an authorized dealer. These parts are guaranteed to fit your engine. Consult your operator’s manual for the correct set of parts for your engine.
On-Going Knowledge
The best way to learn to repair small engines is to be a good owner, and follow the manual. For more information on small engines, there are also plenty of small engine repair books and helpful videos available by certified mechanics and authors.
Most Common Problems
The Repair Clinic troubleshooting system was designed to help you with small engine repair, starting with accurate diagnostics. Choose from our list of symptoms—maybe your lawn mower won’t start or when it does, it sputters or shoots out blues smoke—and we’ll sell you the parts that will fit your model.
The Right Parts for the Job
We carry more than 4 million parts from over 175 major brands, so chances are, we've got the part you need.
Why won't my small engine start?
Determine why your small engine won't start by checking your fuel levels, spark plug, carburetor, valve & compression levels and more. Follow along to troubleshoot and learn when it's best to service your engine.
Why is my outdoor generator not starting?
Stale fuel, dirt, and debris are the most common cause of outdoor power equipment not starting or running properly. If you store equipment with untreated gas in the tank, it can lead to engine damage.
Is your Carburetor clean?
The carburetor regulates how air and fuel move through the engine. A dirty carburetor can cause poor engine performance or starting problems.
Is your Spark Plug faulty?
Disconnected, dirty or fouled spark plugs are common causes for engines that won’t start. For small engines, spark plugs typically need to be replaced every season or after 25 hours of use.
Are you having Ignition problems?
If your spark plugs look good, problems with your ignition system can also be preventing a spark.
Is your Engine's Exhaust smoking?
If the engine is emitting white or blue smoke, this means your engine is burning oil. Check our Engine emits white/blue smoke while running FAQ for assistance.
What happens if you don't have proper valve clearance?
If there isn’t proper valve clearance or there’s a leak, this can cause compression problems that keep an engine from starting. You can perform a compression system with a leak down tester. If you don’t have one of these, we recommend visiting your Briggs & Stratton repair dealer.
Small Engine Repair Questions?
Use the form to send me your questions or to drop off equipment for repair at my shop.
The Small Engine Doctor on YouTube
To get started on repairing and maintaining your own equipment, such as lawnmowers and lawn tractors, snow blowers, chainsaws, generators, pressure washers, tillers, weed whackers and leaf blowers, check out one of my many YouTube videos at donyboy73. Here are the links to some of the most popular:
