You’re out there, ready to conquer your lawn, but your faithful Honda lawn mower is acting up. Instead of the steady purr you’re used to, it’s revving up and down, leaving you frustrated and your grass uncut. This annoying issue can be caused by a variety of factors, from a simple blockage to a more serious engine problem. This article will guide you through the most common reasons why your Honda lawnmower might be revving erratically and provide you with troubleshooting steps to get it back in top shape.
The short answer: A Honda lawnmower that revs up and down is usually a sign of a problem with the fuel system, air intake, or ignition system.
Fuel System Problems
The fuel system is the most common culprit behind erratic engine behavior. When the fuel mixture isn’t reaching the engine correctly, the mower can struggle to maintain a steady speed. Here are some potential issues within the fuel system:
1. Clogged Fuel Filter
The fuel filter is responsible for removing debris and dirt from the fuel before it reaches the engine. A clogged filter can restrict fuel flow, leading to uneven engine performance.
Symptoms:
- Engine sputtering: The engine may sputter or hesitate when you try to accelerate.
- Loss of power: The mower may lose power or struggle to climb inclines.
- Difficult starting: The engine may be difficult to start or take longer to start.
Troubleshooting:
- Inspect the fuel filter: Remove the fuel filter and visually inspect it for dirt or debris.
- Replace the fuel filter: If the filter is clogged, replace it with a new one.
2. Dirty Carburetor
The carburetor mixes fuel and air before it enters the combustion chamber. Over time, dirt and debris can build up in the carburetor, restricting fuel flow and causing erratic engine performance.
Symptoms:
- Engine stalling: The engine may stall unexpectedly, especially at low speeds.
- Black smoke: The engine may emit black smoke from the exhaust.
- Rough idling: The engine may idle roughly or stall at idle.
Troubleshooting:
- Clean the carburetor: Remove the carburetor and clean it thoroughly with carburetor cleaner. Refer to your owner’s manual for specific instructions.
- Replace the carburetor: If the carburetor is severely damaged or worn, it may need to be replaced.
3. Fuel Line Problems
Cracks or kinks in the fuel lines can disrupt fuel flow to the engine, leading to erratic engine behavior.
Symptoms:
- Fuel leaks: You may notice fuel leaking from the fuel lines.
- Engine sputtering: The engine may sputter or hesitate when you try to accelerate.
- Loss of power: The mower may lose power or struggle to climb inclines.
Troubleshooting:
- Inspect the fuel lines: Visually inspect the fuel lines for cracks or kinks.
- Replace the fuel lines: If the fuel lines are damaged, replace them with new ones.
Air Intake Issues
A properly functioning air intake is essential for providing the engine with the necessary air for combustion. A blocked air intake can cause the engine to run lean and result in fluctuating RPMs.
1. Clogged Air Filter
The air filter prevents dust and debris from entering the engine. A clogged air filter restricts airflow, causing the engine to run lean and affecting its performance.
Symptoms:
- Reduced engine power: The engine may lose power or struggle to accelerate.
- Engine sputtering: The engine may sputter or hesitate when you try to accelerate.
- Engine overheating: A clogged air filter can restrict airflow, causing the engine to overheat.
Troubleshooting:
- Inspect the air filter: Remove the air filter and visually inspect it for dirt and debris.
- Replace the air filter: If the air filter is clogged, replace it with a new one.
2. Air Intake Leaks
Leaks in the air intake system can draw in unfiltered air, disrupting the air-fuel mixture and causing erratic engine performance.
Symptoms:
- Engine backfiring: The engine may backfire or run roughly.
- Engine running lean: The engine may be running too lean, leading to overheating and damage.
- Loss of power: The engine may lose power or struggle to accelerate.
Troubleshooting:
- Inspect the air intake system: Visually inspect the air intake system for leaks or cracks.
- Repair or replace damaged components: If you find leaks, repair or replace the damaged components.
Ignition System Issues
The ignition system provides the spark that ignites the air-fuel mixture in the combustion chamber. Problems with the ignition system can lead to misfiring and erratic engine performance.
1. Spark Plug Problems
A worn-out or fouled spark plug can cause misfiring, leading to the engine revving up and down.
Symptoms:
- Engine misfiring: The engine may misfire or run roughly.
- Difficulty starting: The engine may be difficult to start or take longer to start.
- Loss of power: The engine may lose power or struggle to accelerate.
Troubleshooting:
- Inspect the spark plug: Remove the spark plug and visually inspect it for wear and tear.
- Replace the spark plug: If the spark plug is worn or fouled, replace it with a new one.
2. Ignition Coil Issues
The ignition coil is responsible for providing the high voltage necessary to create a spark at the spark plug. A faulty ignition coil can prevent the spark plug from firing properly.
Symptoms:
- Engine misfiring: The engine may misfire or run roughly.
- Difficulty starting: The engine may be difficult to start or take longer to start.
- Loss of power: The engine may lose power or struggle to accelerate.
Troubleshooting:
- Test the ignition coil: Use a multimeter to test the ignition coil for continuity.
- Replace the ignition coil: If the ignition coil is faulty, replace it with a new one.
Other Potential Causes
While fuel system, air intake, and ignition system issues are the most common reasons for a Honda lawnmower revving up and down, other factors can contribute to this problem. These include:
- Engine overheating: If the engine is overheating, it can cause the RPMs to fluctuate.
- Governor problems: The governor is responsible for controlling the engine speed. A faulty governor can cause the engine to run erratically.
- Loose or damaged wiring: Damaged or loose wiring can disrupt the flow of electricity to the engine, causing erratic engine performance.
- Fuel quality: Using low-quality or stale fuel can lead to problems with the fuel system.
Tips for Preventing Revving Issues
To prevent your Honda lawnmower from experiencing revving problems, follow these tips:
- Use fresh fuel: Use fresh, high-quality gasoline.
- Change the air filter regularly: Replace the air filter every 25 hours of operation or as recommended by your owner’s manual.
- Clean the carburetor: Clean the carburetor annually or as needed.
- Inspect the fuel lines: Inspect the fuel lines for cracks or kinks regularly.
- Perform regular maintenance: Follow the maintenance schedule outlined in your owner’s manual.
Conclusion
A Honda lawnmower that revs up and down is a frustrating problem, but it’s usually a solvable one. By systematically troubleshooting potential problems in the fuel system, air intake, and ignition system, you can often pinpoint the root cause and get your mower running smoothly again. If you’re unsure about a repair, it’s always best to consult a qualified mechanic.
FAQs
Why Does My Honda Lawn Mower Rev Up and Down?
This is a common issue that can be caused by a few different things. Here are 7 FAQs to help you diagnose the problem:
1. Why is my Honda lawn mower revving up and down when I’m trying to mow?
This is usually a sign that there is a problem with the carburetor. The carburetor is responsible for mixing air and fuel, and if it’s not working properly, the engine will get too much or too little fuel. This can cause the engine to rev up and down, or even stall completely.
You can try cleaning the carburetor or replacing it if it’s damaged. If the problem persists, you may need to take your mower to a qualified mechanic.
2. My Honda lawn mower is revving up and down when I start it. What’s wrong?
The problem could be a clogged air filter, which restricts airflow and prevents the engine from getting enough air. This can cause the engine to run erratically, including revving up and down.
Replacing the air filter is a simple solution. If the problem persists, you may want to check the fuel lines and fuel filter for any blockages.
3. Why is my Honda lawn mower revving up and down when I let go of the throttle?
This is a sign that the governor on your engine isn’t working properly. The governor is responsible for controlling the engine’s speed, and if it’s not working correctly, the engine will continue to rev up even when you release the throttle.
You can try adjusting the governor linkage or replacing the governor if it’s damaged. If the problem persists, you may need to take your mower to a qualified mechanic.
4. What if my Honda lawn mower is revving up and down after being idle for a while?
This could be due to a faulty choke. The choke is used to enrich the fuel mixture when starting the engine. If the choke doesn’t close properly after the engine warms up, the engine will get too much fuel and rev up and down.
You can try adjusting the choke cable or replacing the choke if it’s damaged. If the problem persists, you may need to take your mower to a qualified mechanic.
5. My Honda lawn mower is revving up and down when I use the blade. Is this a problem with the blade?
While a dull blade can cause a strain on the engine, it’s unlikely to be the root cause of your revving issue. It’s more likely related to the carburetor, fuel system, or governor, as mentioned in previous answers.
However, it’s always a good idea to ensure your blade is sharp for optimal mowing performance and to prevent damage to your lawn.
6. Is there a way to troubleshoot my Honda lawn mower revving problem myself?
Yes, you can start by inspecting the air filter, carburetor, and fuel lines for any blockages or damage. You can also check the governor linkage and choke cable to ensure they’re properly adjusted.
If you’re comfortable with basic repairs, you can try cleaning the carburetor or replacing the air filter. However, if you’re not comfortable working on your mower, it’s best to take it to a qualified mechanic.
7. What should I do if my Honda lawn mower continues to rev up and down despite troubleshooting?
If you’ve gone through the troubleshooting steps and the problem persists, it’s best to take your lawnmower to a qualified mechanic for professional diagnosis and repair. They can identify the underlying issue and provide the appropriate solution.