How To Fix A Mower Engine Kicks Back When Starting?

Ever felt like your mower is giving you a kickback, just like a stubborn horse? It can be frustrating and even dangerous.

But fear not, fixing a mower engine that kicks back when starting is not as daunting as it seems. You can troubleshoot and solve this issue with a few simple steps.

By understanding the problem, checking the spark plug, inspecting the fuel system, examining the ignition system, and adjusting the engine timing, you’ll have your mower starting smoothly in no time.

If you follow these instructions, you’ll be back to mowing your lawn without any unexpected jolts.

Understanding the Problem

When starting your mower engine, it kicks back due to a misalignment of the engine’s components. This misalignment can occur for a few reasons, such as worn-out or improperly installed parts. One common cause is a misaligned flywheel key, which can throw off the timing and cause the engine to kick back.

Another potential culprit could be a faulty ignition system, causing the spark plug to fire at the wrong time. Additionally, a dirty or clogged carburetor may not be delivering the right fuel mixture, leading to erratic engine behavior.

To troubleshoot this issue, start by checking the flywheel key for any signs of damage or wear. If necessary, replace it and ensure it’s properly aligned with the flywheel and crankshaft.

Next, inspect the ignition system for any malfunctions, such as a worn-out spark plug or a faulty ignition coil. Clean or replace these components as needed.

Finally, give the carburetor a thorough cleaning to ensure it’s delivering the correct fuel-air mixture to the engine.

Understanding these potential causes of engine kickback will help you diagnose and fix the issue, getting your mower back in top condition for a smooth start every time.

Checking the Spark Plug

To diagnose the issue of engine kickback, inspect the spark plug for signs of wear or damage. A faulty spark plug can lead to poor ignition, causing the engine to kick back when starting. Follow these steps to check the spark plug:

Step	Action
1. Remove the spark plug	Use a spark plug socket and ratchet to carefully remove the spark plug from the engine.
2. Inspect the spark plug	Look for signs of wear, such as fouling, corrosion, or damage to the electrode. If the spark plug appears dirty or damaged, it may need to be replaced.
3. Measure the spark plug gap	Use a feeler gauge to check the spark plug gap, ensuring it is within the manufacturer’s specifications. If the gap is too wide or too narrow, it can affect the engine’s performance.

Inspecting the Fuel System

First, check the fuel lines for any cracks or leaks that could be causing fuel delivery issues.

Then, inspect the fuel filter for clogs or debris that may be obstructing the flow of fuel to the engine.

Lastly, clean the carburetor components to ensure that the fuel is being properly mixed with air for combustion.

Check Fuel Lines

You should begin by inspecting the fuel lines for any signs of damage or blockage. Here’s how to do it:

1. Visual Inspection: Check the fuel lines for cracks, kinks, or any visible signs of wear and tear.

2. Flexible Hoses: Ensure that the fuel lines are flexible and not hardened or brittle, as this could indicate deterioration.

3. Blockage Check: Look for any obstructions within the fuel lines that could be hindering the flow of fuel to the engine.

4. Leak Test: Examine the fuel lines for any leaks or seepage, as this could lead to a loss of fuel pressure and affect engine starting.

Inspect Fuel Filter

After thoroughly inspecting the fuel lines for any damage or blockage, you should now turn your attention to the fuel filter as the next component to examine in the fuel system.

The fuel filter plays a crucial role in ensuring that clean fuel reaches the engine. Start by locating the fuel filter, which is typically situated between the fuel tank and the carburetor. Remove the filter and inspect it for any signs of clogging, dirt, or damage.

If the filter appears dirty or clogged, it’s essential to replace it with a new one to ensure proper fuel flow. Additionally, check for any sediment or debris in the fuel filter housing that may indicate impurities in the fuel system.

Regular inspection and replacement of the fuel filter can help prevent engine kickback issues when starting.

Clean Carburetor Components

To resolve the issue of engine kickback when starting, begin by cleaning out the carburetor components to ensure proper fuel delivery. Follow these steps to clean the carburetor components effectively:

1. Remove the carburetor: Start by disconnecting the spark plug wire and removing the air filter. Then, disconnect the fuel line and carefully detach the carburetor from the engine.

2. Clean the carburetor body: Use a carburetor cleaner to spray and clean the exterior and interior of the carburetor body, including the throttle plate and linkage.

3. Inspect the fuel inlet and outlet: Check for any blockages or debris in the fuel inlet and outlet. Use a small wire or carburetor cleaner to clear any obstructions.

4. Reassemble the carburetor: Once cleaned, reassemble the carburetor and reattach it to the engine, reconnect the fuel line, air filter, and spark plug wire.

Examining the Ignition System

When examining the ignition system of your mower engine that kicks back when starting, check the spark plug for any signs of wear or damage. A worn-out or damaged spark plug can cause the engine to kick back when starting. Inspect the spark plug for cracked porcelain, worn electrodes, or heavy carbon buildup. If any of these issues are present, replace the spark plug with a new one that matches the manufacturer’s specifications.

Next, examine the ignition coil and the spark plug wire. Make sure the spark plug wire is securely connected to both the spark plug and the ignition coil. If the wire is loose or damaged, it can cause intermittent sparking, leading to engine kickback. Additionally, inspect the ignition coil for any visible damage or discoloration. If the ignition coil is faulty, it may not provide the necessary spark for a smooth start.

Adjusting the Engine Timing

To adjust the engine timing, start by checking the tension of the timing belt.

Then, make sure to adjust the ignition timing to the manufacturer’s specifications.

Timing Belt Tension

Once you have identified that the timing belt tension may be causing the engine to kick back when starting, you can take steps to adjust the engine timing.

Here’s how to adjust the timing belt tension:

1. Locate the Timing Belt: First, you need to find the timing belt in your mower’s engine. It’s usually covered by a protective casing.

2. Loosen the Tensioner: Use the appropriate tools to loosen the tensioner and create slack in the timing belt.

3. Adjust the Tension: Once the tensioner is loosened, you can adjust the tension of the timing belt to the manufacturer’s specifications.

4. Tighten the Tensioner: After adjusting the tension, make sure to tighten the tensioner back to secure the timing belt in place.

Proper timing belt tension is crucial for the smooth operation of the engine and can help prevent it from kicking back when starting.

Ignition Timing Adjustment

Loosening the distributor bolt, you can adjust the ignition timing of your mower’s engine to prevent it from kicking back when starting.

Start by locating the distributor, usually found near the engine block.

With a timing light, you can see the marks on the crankshaft pulley and the proper timing degree indicated on the engine.

Next, connect the timing light to the battery and spark plug wire, and start the engine to observe the timing marks.

If the marks don’t align with the specified degree, loosen the distributor bolt and adjust the timing by turning the distributor.

Once the marks are aligned, tighten the bolt and recheck the timing to ensure it remains accurate.

Proper ignition timing can significantly reduce the risk of kickback when starting the mower’s engine.

Valve Timing Adjustment

You can adjust the valve timing of your mower’s engine to improve its performance and prevent kickback when starting. Here’s how to do it:

1. Locate the Timing Marks: Find the timing marks on the crankshaft and camshaft gears. These marks indicate the proper alignment for the valve timing.

2. Adjust the Camshaft Position: Loosen the camshaft gear and rotate it to align with the timing marks. This ensures that the intake and exhaust valves open and close at the correct times.

3. Tighten the Camshaft Gear: Once the camshaft is in the correct position, tighten the gear to secure the new timing alignment.

4. Check and Test: Double-check the alignment of the timing marks and then start the mower to ensure the engine runs smoothly without any kickback.

Seeking Professional Help

When encountering persistent issues with your mower engine kicking back when starting, consider seeking professional help to diagnose and resolve the problem effectively. A professional can provide expertise and specialized tools to identify the root cause of the issue and ensure that the correct repairs are made. Here are some reasons why seeking professional help may be the best course of action:

Reasons to Seek Professional Help
Expertise	Professional mechanics have the knowledge and experience to accurately diagnose and fix mower engine issues.
Specialized Tools	Professionals have access to specialized tools that may not be readily available to the average person, allowing for more precise repairs.
Warranty Considerations	If your mower is still under warranty, having a professional perform the repairs may be necessary to maintain the warranty coverage.
Time and Convenience	Hiring a professional saves you time and effort, allowing you to focus on other tasks while the issue is being resolved.

Seeking professional help can save you the frustration of attempting multiple DIY fixes, and it ensures that your mower engine is in the best hands for repair.

Frequently Asked Questions

Can Using Old or Stale Gasoline in My Mower Contribute to the Engine Kicking Back When Starting?

Using old or stale gasoline in your mower can indeed contribute to the engine kicking back when starting. This is often due to the fuel’s decreased volatility and potential buildup of varnish and debris in the carburetor.

How Often Should I Replace the Air Filter in My Mower to Prevent Starting Issues?

You should replace the air filter in your mower annually to prevent starting issues. Regular replacement ensures proper airflow and helps maintain engine performance. A clogged filter can lead to difficulty starting and poor running.

What Are Some Common Mistakes People Make When Trying to Start a Mower That Can Cause the Engine to Kick Back?

When starting a mower, avoid pulling the cord too forcefully or using too much choke. Also, ensure the fuel is fresh and the spark plug is in good condition. These common mistakes can cause the engine to kick back.

Are There Any Specific Brands or Types of Spark Plugs That Are Known to Cause Kicking Back Issues in Mower Engines?

When starting a mower, specific spark plug brands or types can cause kicking back issues. Make sure to use the recommended spark plug for your mower model, as using the wrong one can lead to engine problems.

Can Extreme Temperatures, Such as Very Cold or Very Hot Weather, Affect the Starting of a Mower Engine and Cause It to Kick Back?

Yes, extreme temperatures can affect mower engine starting. In very cold weather, the oil can thicken, making it harder to turn over. In very hot weather, vapor lock or fuel evaporation can cause starting issues.

Conclusion

Now that you’ve gone through the steps to fix a mower engine that kicks back when starting, you should have a better understanding of the potential causes and solutions for this issue.

By checking the spark plug, inspecting the fuel and ignition systems, and adjusting the engine timing, you can address the problem and get your mower running smoothly again.

If you’re still having trouble, don’t hesitate to seek professional help for further assistance.