8 Most Common John Deere Z930M Problems

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By Marvin Tucker

Farming Equipment

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No weed is safe when you have a John Deere Z930M on your property. This small but practical lawn mower is a true hard worker. Plus, the zero-turn sure helps speed things up!

Despite all its good qualities, some users have found some issues with this lawn mower, specifically regarding its engine, fuel filter, blades, transmission, and electrical system.

Is it as bad as it seems, or is this John Deere mower still worth a shot? Let’s find out!

The most common problems with John Deere Z930M

From compact tractors to garden tractors, John Deere sure makes trustworthy machines. Indeed, this brand is a leader in the market, and when you buy one of their products, you know you’re in for a good ride.

The Z930M is a zero-turn mower, which means that when you’re done working in a specific direction, this mower can make a 180° turn and start working in the opposite direction right away.

This is one of the many reasons why this lawn mower from John Deere is so loved, but with so many good qualities, it also has some flaws.

When we tried this model, we didn’t expect any significant issues and were surprised to find more than a few.

When comparing our experience with other users, we found that some of the issues we’re going to describe below are relatively common with this model. Plus, we found new ones we didn’t experience.

So, what are the most common problems with John Deere Z930M? If you want all the details, keep reading!

1. Engine noise issue

With this John Deere, there’s a lot of backfiring and sputtering. When the engine doesn’t work correctly, there could be many reasons.

With the Z930M, it seems that most often, the problem is the PTO, which “steals” power from the main engine. It’s easy to check if the PTO is the problem: it’s enough to remove the blades from the equation.

You should also check all components and switches to see if they work correctly. If the PTO is not the issue, you should check the air filter system and clean or replace it when necessary.

Fundamentally, this system remains in good health for your mower’s longevity and functioning.

Finally, the most obvious but also the most essential thing to check is fuel. It should be fresh, it should be good quality, and it should be the right type for your John Deere.

The fuel tank should be filled to the right level, and the fuel filter should be clean. Maintenance of the fuel system is of utmost importance.

2. Fuse issue

When the engine is in good condition but won’t start, the battery may have a problem. Now, to check whether the problem is the battery itself, or some connection, you should jump-start the battery.

If the problem remains, you probably have a bad fuse.

This happens the most when you haven’t used the mower in a while. If it has been sitting still for a few weeks, you might have the stator and the main fuses completely blown.

The first thing to do is to check the battery with a multimeter DC/A. If the voltage reads below 10.5, replace the battery. It should read 12.5-12.9 volts; anything less requires charging.

If the problem is the fuse, put the holders in line and check for the ignition power. We’re looking for 12 volts here. In the case your mower is new, don’t start splicing wires. Get a new 20 amp fuse from Deere and see how it goes.

3. Ignition coil issue

When you have damage in your ignition coil, the signs are pretty evident: the mower is hard to start, performs quite poorly, and only runs when you play with the plug wire.

Here’s what you can do about it:

  1. Remove the boot from the spark plug and replace it with the spark tester’s boot.
  2. Connect the original spark plug boot to the tester through its free end.
  3. Start the mower from a cold engine and look through the window of the tester. You should see the spark that typically allows the mower operations.
  4. Replace the spark plug boot with the original. Once you start the engine, replace the tester as well.
  5. Bring your mower to temperature with some action, for example, by mowing some grass.
  6. The mower will stop by itself. Now use the in-line spark tester to replace the old wire.
  7. If there’s no spark, look for the same spark level as when the mower was cold.
  8. If there is a little-to-no spark, the ignition coil is faulty and needs replacement. But the problem is elsewhere if the spark is good and the mower still won’t move.

4. Fuel filter issue

Having a problem with the fuel filter is something you wouldn’t wish upon your worst enemy.

This small component can wreak havoc on your mower, causing overheating, stalling, starting issues, sputtering, etc.

Cleaning a fuel filter from debris is difficult and won’t necessarily bring the results you expect. In this case, it would be better to replace it right away.

5. Blades issue

When you have mower blades that are not turning or continuously start and stop, you might have a problem with the safety switch.

This switch is usually under the driver’s seat and should stop the blades when there’s no weight on the seat, such as when you’re not on the mower.

A faulty safety switch is a severe health hazard, so ensure it’s always turned on.

However, it should only stop the blades when any of the other switches are tripped. If it prevents the blades from working, it needs replacement.

6. Transmission issue

Some John Deere Z930M users complain about transmission noises. Usually, this is due to the transmission fluid being contaminated.

The only way to fix this issue is to remove the caps and check for yourself. Follow this procedure:

  1. Turn off the engine and remove the transmission key.
  2. Make sure the blades are disengaged, and the brake is engaged.
  3. Remove the battery and unplug it.
  4. You will find the drain pans under each side of the transmission tank. Remove the caps on each side with a socket wrench.
  5. Drain the reservoir and remove any excess liquid.
  6. If necessary, replace the filters as well.
  7. Refill the reservoir and pour fresh transmission fluid.

7. Transaxle issue

The John Deere Z930M uses a TZT-13 zero turn IHT (Integrated Hydrostatic Transaxle), which unfortunately is known for having a high risk of leaking without showing signs of doing so.

This problem is so common with this model that usually, John Deere will repair it when you’re under warranty.

You cannot fix the transaxle leaking problem by yourself unless you have the right tools and knowledge, but you can order necessary replacement parts from John Deere if you want to try.

We recommend getting professional assistance, which usually takes 4-8 hours to fix.

8. Starting issue

Many other mowers and tractors have this same issue.

The starting issue doesn’t have a single cause; many problems could provoke it, but usually, it’s either the fuel system or the carburetor cut-off valve.

The first thing to check would be the latter, as this has a plug into the engine of the main jet and might stop fuel from getting into the machine.

This valve is placed in a small canister at the bottom of the carburetor and works with an ignition switch. Make sure it’s set on ON.

If you believe it’s the fuel system:

  1. Make sure the fuel tank is filled with fresh fuel.
  2. Check for clogged fuel lines.
  3. Check for a dirty fuel filter.
  4. If it has been raining, check if there’s water in the fuel.

John Deere Z930M problems: are they a deal-breaker?

No, we don’t feel like condemning this model from John Deere for the issues we just described.

Many of these issues are pretty common with this type of machine, no matter the brand you have at home. Most of them are easily prevented with regular maintenance of the mower.

John Deere Z930M is an excellent, sturdy, durable, and hardworking zero-turn mower.

It will surely last for a long time, and as such, it may have a few bumps on the way, but don’t let this discourage you if that’s the model you want to go for!

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