John Deere Z335E Problems: Troubleshooting Common Issues

If you’re a proud owner of a John Deere Z335E lawn mower and have been facing frustrating problems with its engine performance, you’re not alone. Many users have encountered similar issues, and in this article, we’ll delve into some of the common problems reported by Z335E owners and explore possible solutions to help you get your mower running smoothly.

6 John Deere Z335E Problems

Problem 1: Engine Surging

One of the most frequently reported problems with the John Deere Z335E is engine surging, where the engine seems to fluctuate in RPM (revolutions per minute) when not under load. This can be a perplexing issue, but there are several potential solutions to consider.

Solution 1: Valve Adjustment and Engine Cleaning

One user suggested adjusting the engine valves. The recommended valve adjustment for the Briggs and Stratton 20HP 656cc engine is intake valves at 0.004 – 0.006 inches and exhaust valves at 0.004 – 0.006 inches. Additionally, clean the engine thoroughly, paying attention to the cooling fins, which can accumulate debris that affects engine performance.

Solution 2: Fuel Treatment

Another recommendation is to add a small bottle of Star Tron Fuel Treatment to your gas can, following the instructions on the bottle. This additive can help improve fuel quality and combustion.

Problem 2: Sputtering and Engine Stalling

Another common issue is the engine sputtering and stalling after a short period of operation, typically around 45 minutes. This problem can be particularly frustrating and is often related to fuel supply or ignition.

Solution 3: Inspect Fuel System

Debris in the fuel tank can partially block the outlet, causing the engine to stall. Check the fuel tank for any obstructions and clean it as necessary. This may involve removing the tank or fuel pickup tube to access and remove any debris.

Solution 4: Test Ignition System

To determine if the problem is related to the ignition system, you can use inline spark testers on the spark plugs while mowing. If the engine dies and the spark testers show erratic behavior, it may indicate an ignition or coil problem.

Problem 3: Fuel Delivery Issues

Some users have noticed that the fuel filter does not remain consistently full, which can lead to fuel delivery problems and engine surging.

Solution 5: Understanding Fuel Filter Behavior

It’s important to note that the fuel filter may not always appear full while the engine is running because the fuel pump draws fuel through it. When the engine is off, gravity can cause fuel to fill the filter. If your filter appears empty while the engine is running, it might not necessarily indicate a problem.

Solution 6: Investigate the Fuel System

If you suspect a fuel flow problem, consider examining the entire fuel system, from the tank to the carburetor. Pay close attention to the fuel lines, fuel pump, and filter to ensure they are clean and functioning correctly.


While the John Deere Z335E is a popular and reliable lawn mower, some users have encountered issues like engine surging, sputtering, and stalling. By following the suggested solutions, you can troubleshoot these problems and keep your Z335E running smoothly, ensuring your lawn stays well-maintained without frustration. Remember to perform regular maintenance and consult your owner’s manual for specific guidance on maintaining your mower.