28/04/2019
Briggs & Stratton engines are a staple in the world of small-engine powered equipment, from lawnmowers and generators to pressure washers and go-karts. Their ubiquity, however, doesn't mean they are immune to problems. Understanding common faults and how to address them can save you time, money, and a great deal of frustration. Whether you're a seasoned mechanic or a DIY enthusiast, this guide will walk you through the most frequent issues encountered with Briggs & Stratton small engines and provide practical solutions.
- Starting Troubles: The Most Common Complaint
- Engine Runs But Lacks Power
- Engine Overheating
- Engine Stalling or Shutting Off
- Troubleshooting Table: Common Issues and Solutions
- When to Consider Professional Help
- The Importance of Regular Maintenance
- Considering a New Engine?
- Frequently Asked Questions
Starting Troubles: The Most Common Complaint
One of the most disheartening issues a user can face is an engine that simply refuses to start. This can manifest in several ways: no cranking, weak cranking, or cranking but no ignition. Let's break down the potential culprits:
Fuel System Issues
A small engine needs a precise mixture of fuel and air to combust. If this mixture is off, starting becomes impossible. The fuel system is often the primary suspect:
- Stale Fuel: Petrol degrades over time, especially if it contains ethanol. Old fuel can gum up the carburettor and fuel lines, preventing fuel from reaching the combustion chamber. Always use fresh fuel, ideally within 30 days of purchase, or use a fuel stabiliser if storing for longer periods.
- Clogged Carburettor: This is a very common problem. Varnish and debris from stale fuel can block the tiny jets and passages within the carburettor. Symptoms include difficulty starting, rough idling, and loss of power. Cleaning the carburettor, or even replacing it, is often necessary.
- Blocked Fuel Filter: If your engine has a fuel filter, a blockage will restrict fuel flow. Regularly check and replace the fuel filter as per your engine's manual.
- Fuel Line Obstruction: Kinks or blockages in the fuel line can also starve the engine of fuel. Ensure the fuel line is clear and undamaged.
Ignition System Problems
Even with a perfect fuel-air mixture, the fuel won't ignite without a strong spark. The ignition system is the next area to investigate:
- Spark Plug Issues: A fouled, damaged, or incorrectly gapped spark plug is a frequent cause of no-start or misfiring. Remove the spark plug, check its condition (look for black, oily, or white deposits), clean it with a wire brush, and ensure it's gapped correctly according to your engine's specifications. If it's worn or damaged, replace it. The spark plug is a critical component.
- Faulty Ignition Coil: The ignition coil generates the high voltage needed to create a spark. If the coil fails, you won't get a spark. This can be tested using a multimeter, but often requires replacement.
- Loose or Damaged Wiring: Ensure all wiring connections to the ignition system are secure and free from corrosion or damage.
Air Intake Obstructions
Air is just as vital as fuel. A blocked air filter will choke the engine:
- Dirty Air Filter: A clogged air filter restricts airflow to the carburettor, leading to a rich fuel-air mixture, poor performance, and difficulty starting. Check and clean or replace the air filter regularly. This is one of the simplest maintenance tasks you can perform.
Engine Runs But Lacks Power
If your engine starts but runs poorly, sputtering, or losing power under load, the issues are often related to the fuel or air systems, or potentially internal engine problems:
Fuel Delivery and Mixture
- Partially Clogged Carburettor: Even if it starts, a partially blocked carburettor can cause poor performance, especially under load.
- Incorrect Choke Setting: Ensure the choke is adjusted correctly. If it's partially closed when the engine is warm, it can cause a rich mixture and bogging down.
- Low Compression: While less common, low compression can significantly reduce power. This could be due to worn piston rings, valves, or a damaged cylinder head gasket.
Exhaust System
- Blocked Muffler: A clogged muffler, often due to carbon build-up or insect nests, can create excessive backpressure, hindering performance.
Engine Overheating
Overheating can cause significant damage. Common causes include:
- Blocked Cooling Fins: Briggs & Stratton engines typically use air cooling. If the cooling fins on the engine block and cylinder head are caked with dirt, grass clippings, or debris, airflow is restricted, leading to overheating. Regular cleaning of cooling fins is essential.
- Low Oil Level: Oil not only lubricates but also helps dissipate heat. Running an engine with insufficient oil can cause it to overheat rapidly. Always check and maintain the correct oil level.
- Lean Fuel Mixture: An overly lean fuel-air mixture (too much air, not enough fuel) can cause the engine to run hotter than normal.
Engine Stalling or Shutting Off
An engine that starts and then stalls can be caused by a variety of factors:
- Fuel Cap Vent Blockage: The fuel cap has a small vent to allow air into the tank. If this vent is blocked, a vacuum can form, preventing fuel from flowing. Loosening the fuel cap might temporarily resolve the issue.
- Overheating: As mentioned, overheating can cause an engine to shut down as a protective measure.
- Oil Level Sensor (if equipped): Some engines have a low-oil sensor that will shut off the engine if the oil level drops too low.
- Intermittent Ignition or Fuel Supply: A loose connection in the ignition system or an intermittent blockage in the fuel line can cause the engine to cut out unexpectedly.
Troubleshooting Table: Common Issues and Solutions
Here's a quick reference guide for common Briggs & Stratton problems:
| Symptom | Potential Cause(s) | Solution |
|---|---|---|
| Engine won't start | Stale fuel, clogged carburettor, fouled spark plug, no spark, blocked air filter | Drain old fuel, clean/replace carburettor, clean/replace spark plug, check ignition, clean/replace air filter |
| Engine starts but runs rough | Partially clogged carburettor, incorrect choke setting, dirty air filter, spark plug gap incorrect | Clean carburettor, adjust choke, clean/replace air filter, check spark plug gap |
| Loss of power | Clogged carburettor, blocked fuel filter, dirty air filter, low compression, blocked muffler | Clean/rebuild carburettor, replace fuel filter, clean/replace air filter, check compression, clear muffler |
| Engine overheats | Blocked cooling fins, low oil level, lean fuel mixture | Clean cooling fins, check/add oil, check fuel mixture/carburettor |
| Engine stalls | Blocked fuel cap vent, overheating, low oil shutdown, loose ignition wiring | Clean fuel cap vent, check cooling, check oil level, secure wiring |
When to Consider Professional Help
While many common issues can be resolved with basic maintenance and a few tools, some problems may require more advanced diagnostic skills or specialised equipment. If you've tried the basic troubleshooting steps and the engine still isn't running correctly, or if you suspect internal engine damage (e.g., low compression, metal shavings in the oil), it's best to consult a qualified small engine mechanic. They have the expertise and tools to diagnose and repair more complex issues.
The Importance of Regular Maintenance
Preventing problems is always better than fixing them. Establishing a regular maintenance schedule is key to ensuring your Briggs & Stratton engine performs reliably for years to come. This typically includes:
- Oil Changes: Follow the manufacturer's recommendations for oil type and change intervals.
- Air Filter Cleaning/Replacement: Do this at least annually, or more often if operating in dusty conditions.
- Spark Plug Inspection/Replacement: Replace annually or as needed.
- Fuel System Care: Use fresh fuel and consider a fuel stabiliser. Drain the carburettor if storing the engine for extended periods.
- General Cleaning: Keep the engine clean, especially the cooling fins.
Considering a New Engine?
If your current Briggs & Stratton engine is beyond economical repair, or if you're looking for an upgrade, purchasing a new engine is a viable option. For instance, a 6.5 hp Briggs and Stratton engine is a popular choice for many applications due to its balance of power and efficiency. When selecting a new engine, consider factors like horsepower, shaft size and type, and mounting patterns to ensure compatibility with your equipment. Reputable suppliers offer a wide selection and can provide expert advice to help you make the right choice. Investing in quality replacement parts, like original Briggs & Stratton parts, also ensures optimal performance and longevity for your equipment.
Frequently Asked Questions
Q: How often should I change the oil in my Briggs & Stratton engine?
A: Always refer to your specific engine's manual. However, a general guideline is every 25-50 hours of operation or annually, whichever comes first. Check the oil level before each use.
Q: My engine starts but then dies. What could be wrong?
A: This is often due to a blocked fuel cap vent, a partially blocked fuel line, or an overheating issue. Try loosening the fuel cap, checking the fuel lines, and ensuring the cooling fins are clean.
Q: Can I clean a carburettor myself?
A: Yes, for many common blockages, you can clean a carburettor using carburettor cleaner spray and compressed air. However, if the blockage is severe or you're uncomfortable doing so, it's best left to a professional.
By understanding these common issues and implementing regular maintenance, you can keep your Briggs & Stratton small engine running efficiently and reliably for many years. Don't underestimate the power of simple maintenance!
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