6 Familiar John Deere SST18 Problems, Causes & Easy Fixes!

The John Deere SST18 lawn mower is popular for utilizing Spin Steer Technology (SST). This feature ensures a zero-turn radius, allowing unmatched maneuverability and speed. But even with its reliable cutting performance, the mower is vulnerable to a few problems.

So, what are these common John Deere SST18 problems? The issue with the power steering is the most frequent. This lawnmower is also prone to stalling problems and the throttle getting stuck. Other issues you may encounter include a faulty charging light, the mower not starting, and not suddenly moving.

Interested in learning more about John Deere SST18 issues? Take your time to go through our comprehensive guide.

Problems With The John Deere SST18 & Possible Solutions Table

Below is a table summarizing the typical problems of John Deere SST18 and how to fix them.

Steering IssuesReplace the faulty vacuum actuators
Change the steering fluid and filter
Replace the faulty switches
Stops Moving SuddenlyTighten or replace the pedal linkage
Replace the transmission pulley splines
Change the forward/reverse actuators
Throttle ProblemClean the throttle cables
Lubricate the throttle
Replace the throttle cable
Adjust the throttle lever position
StallingReplace the fuel and air filter
Clean the carb jet and fuel line
Replace the gas cap
Recharge the battery
Charging Light ProblemClean the corroded battery wires
Tighten loose wire connections
Replace the regulator
Replace the damaged relays
Engine Won’t StartReplace the faulty switches
Change the ignition switch
Connect or tighten the seat switch

Common John Deere SST18 Problems and Solutions Discussed

The John Deere SST18 is a reliable lawn tractor with excellent features, including power steering and zero turn radius. However, this lawn tractor is susceptible to various issues, which include:

1. Steering Problems

The steering of the John Deere SST18 has issues when turning it to the right forward. Basically, the steering wheel may hesitate to turn and clunk a little bit before eventually turning.

However, with some models, the steering wheel may fail to turn left or right, whether moving forward or reverse. Sometimes, the steering will only turn right or left.

One of the common causes of these steering problems is faulty vacuum actuators and switches. Clogged steering filters may also result in steering issues.


You can fix JD SST18 steering problems by following the steps below:

Step 1: Test the vacuum actuators by disconnecting the vacuum hoses and pulling a vacuum on them. Then, replace only the actuators that are not working.

Step 2: Change the steering filters and fluid.

Step 3: Test the steering switch and the switches on the foot pedal linkage. Then, replace those not working.

Tip: Always inspect the steering wheel and shaft for any signs of damage to minimize frequent problems.

2. Stops Moving Suddenly

While mowing, your JD SST18 may suddenly quit moving even when the engine is running. Simply, the mower may fail to move forward or backward. This problem occurs despite the belt and pulleys being in good condition.

Apart from faulty forward and reverse actuators, another cause of this problem could be stripped-out transmission pulley splines. It could also occur due to a loose or broken pedal linkage.


So, keeping the above in mind, below are steps on how to solve this problem:

Step 1: Tighten the pedal linkage if it’s disconnected or replaces it if broken.

Step 2: Replace the transmission pulley splines if they are stripped out.

Step 3: Get new forward/reverse actuators.

Tip: Regularly check if the transport rod on the back is pushed in and not pulled out. It could cause your SST18 to suddenly stop moving.

3. Throttle Issue

The throttle may get stuck in the highest position after mowing and fail to bulge. Basically, the throttle will get stuck more towards the lever and not the carburetor. A sticky throttle could be due to a lack of lubrication in the cables, worn cables, or the cables getting wound.


So, the following are step-by-step instructions to help you fix this problem:

Step 1: Clean the throttle cable to remove any dirt, rust build-up, and debris.

Step 2: Spray some lubricant like WD-40 on the moving parts of the throttle.

Step 3: Replace the throttle cable if it is broken.

Step 4: Adjust the throttle lever position.

Tip: Don’t disassemble the throttle because failure to put it back together correctly may cause irreversible motor damage.

4. Stalling

Sometimes, the John Deere SST18 may start and run great for around 15 minutes before stalling. And if you shut off the PTO and blades, it starts working again for a minute or two.

With other SST18 units, the lawn mower will stall when you increase the throttle or engage the cutting blades. Conversely, some SST18 models will stall immediately after you release the choke.

Besides a clogged fuel line, air filter, and fuel filter, a faulty gas cap vent could cause this problem. A dirty carburetor jet and low battery voltage may also cause stalling problems.


Following are simple steps on how to solve this problem:

Step 1: Change the fuel and air filter.

Step 2: Clean the fuel pipes and carburetor jet.

Step 3: Replace the gas cap.

Step 4: Recharge the battery if the voltage is below 13.2 volts.

Tip: Don’t let your SST18 stay idle for a long time. Instead, run it at least monthly, making sure to add fresh fuel.

5. Charging Light Issue

With the 2001 SST18, the battery charge light may come on intermittently when the mower is running. This occurs even when the battery is fully charged at 13.8 volts.

The likely cause of the charging light problem is a loose wire, corrosion, or a short in one of the battery wires. Sometimes, it could also be due to a bad relay or voltage regulator.


To solve this problem, you will need to follow the following steps:

Step 1: Check if the battery wires are corroded and clean them.

Step 2: Tighten any loose wires.

Step 3: Install a new regulator.

Step 4: Replace any damaged relays.

Tip: Test the battery and wires for voltage before replacing any part.

6. Engine Won’t Start

Additionally, the John Deere SST18 may fail to start. This issue occurs even when the brakes are on. After running jumpers, the mower may start but die when you engage the PTO.

Apart from a faulty plunger switch, a bad seat switch, PTO switch, and brake switch can cause this problem. Sometimes, the issue could be with the ignition fuse or a loose seat safety switch.


Below are the steps you must follow to solve this problem:

Step 1: Check if all the switches are working and replace them.

Step 2: Replace the ignition fuse.

Step 3: Connect or tighten the seat switch.

Tip: Always ensure the brake, seat, and PTO switches are working, as they can keep your mower’s starter from working.


The John Deere SST18 mowers are reputed mainly for their reliability. Still, they are prone to several issues. For example, these lawnmowers sometimes stall or fail to start and move. In other cases, the mowers may suffer from a stuck throttle.

The good news? These problems don’t happen all that often. Even better, many ways exist to troubleshoot all these problems, ensuring their long-lasting performance. John Deere also offers troubleshooting information for some of these issues.

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