How Do I Know If My Zero Turn Mower Has A Pump Or Wheel Motor?

Some zero-turn mowers run on hydraulic pumps and some run on wheel motors. So how do you know the difference? It’s easy; there are a few differences you can figure out by checking the gear.

The short answer is in how the fluids are transferred to the motor. Wheel pumps circulate hydraulic oil through pipes and hoses to convert energy. While the wheel motor powers the wheels and makes it easy to drive. 

This may sound confusing, but we’ll discuss how to tell the differences on your mower in further detail below. It’ll help you troubleshoot your zero-turn and save money in the process. 

What If Your Zero-Turn Mower Is Acting Oddly? 

You may find the lawnmower failing to drive straight, the engine stalling, or the mower causing a racket when you’re using it. So, is it the pump or the wheel motor?

More often than not, problems that appear with zero-turn mowers are related to these two. Otherwise, it may be the oil leaking or something else.

How to Know If Your Mower Runs on a Hydraulic Pump or a Wheel Motor

Not all zero-turn mowers are the same. Some run on conventional wheel motor systems, and some are more advanced, running on hydraulic pumps.

Look for the gear teeth to know whether your mower operates on a wheel motor or a hydraulic pump. A wheel motor’s gear should show more projections on the edge than a hydraulic pump system gear. On top of that, if your zero-turn mower has a pump, you’ll find an oil discharge port and a larger one for suction on it.

Another difference is that mowers with hydraulic pump systems deliver higher speeds than wheel motors.

How Do I Know If My Zero Turn Mower Has a Pump Or Wheel Motor Issue?

To know whether your zero-turn mower has a pump or wheel motor issue is to look at the engine. It may sound complicated, but we’ll walk you through what to look for. 

For starters, disconnect the motor from the mower’s system and remove all the fittings or hoses, depending on your model. Now that the mower is plugged off, the oil supposedly can’t flow because, as far as the system knows, the wheels are locked or the parking brake is on.

Now, you’ll start the lawnmower, but bear in mind that it should be blocked against something, or else it may runoff. After you start the machine, push the levers forward. If your pump is OK and there’s no problem with it, the levers shouldn’t go forward all the way. 

You should only be able to push them halfway through or a bit more. The pump should stall the engine button because the wheels are supposedly locked.

So, in this case, if you can push the lever all the way forward without the machine stalling, the pump is definitely flawed and needs replacement or repair. On the other hand, if it’s working fine, it should stall, and you shouldn’t be able to push the levers all the way forward. 

The thing with this method is that there’s no way to know if the wheel motor is flawed. The best it can do is let you know whether the pump is good. So if it’s good, your mind automatically goes to the possibility that there’s something wrong with the wheel motor.

Zero Turn Mower Troubleshooting

There are a lot of common mistakes that you most likely will encounter at some point. While not all zero-turn mowers are created equal, they mostly show the same problems. Here are a few common issues and how to solve them.

Engine Not Starting

The engine not starting is a common problem in all zero turn mowers are gas-powered machines. You may hear a weird sound or a screech from the engine, and it won’t start. 

In this case, the problem is likely a result of a clogged filter, malfunctioning spark plugs, or a faulty engine. In some cases, it’ll be a simpler reason, such as an empty fuel tank. Battery-operated mowers may also refuse to start if the battery is expired.

If this happens to you, the first thing to do is check the air filter. Then, if it’s clean, check the oil and the spark plugs. The problem will likely be in one of those, but it’s better to ask for professional help if it’s not.

Engine Running Weakly

Sometimes, the engine will start as it usually does, but it’ll run weakly. You may find it making higher sounds than usual or pushing the mower too hard. This mostly happens due to wrong fuel mixtures. In this case, you’ll want to ask a professional about the fuel you’re using and whether you need to change it.

If it’s not that, the spark plugs may need replacement.

Brakes Not Working

It sometimes happens that the blades stop working or take too long to respond. For example, you may run over something by accident or notice they’re too slow to stop the machine. In this case, the reason is that they’re likely installed incorrectly.

That’s if your zero-turn mower is new. If it’s old, then the brake pads likely need replacement.

You should first check that the brake setting is adjusted correctly and that the brakes are correctly installed. Then, if all is well, start checking the brake pads.

Mower Cutting Unevenly

More often than not, uneven cuts are due to blade damage. You’ll know that there’s something wrong when you see the mower cutting the grass in an irregular pattern. If that happens, the reason is either a faulty blade installation, a damaged blade, or an incorrectly-leveled deck.

The first thing you should check is the blade, then take a look at the deck and spindle. Any part that’s working incorrectly will likely need to be replaced.

Hydraulic Transmission Failing

Sometimes, the mower’s transmission will fail, and you’ll find that the mower’s wheels are refusing to move. It may be because of clogged filters, an overturned pulley, or a ruptured transmission. In most cases, you’ll have to replace one or two parts.

The first thing you should do is check the motor and make sure it’s working. Then, take a look at the wiring.

If all is well, the problem may be happening because of a faulty pump.

Engine Knocking

If your mower’s engine is knocking or making weird sounds, the problem is likely because of a low oil level. Or, there’s a chance you’re using the wrong oil type for your machine. In this case, the only way to fix it is to put the right oil at the right level. If it’s your first time owning a mower, it’s better to read the instructions manual first.

Mower Vibrating Loudly

No one likes to work with a loud vibrating noise in the background. Unfortunately, loud vibration is a common issue with zero-turn mowers, and it mainly happens due to faulty deck belts or blades. 

When you hear the sound or feel the machine vibrating excessively, check the mounting bolts of the blades. They may be loose and need tightening.

If that’s not the case, see if the pulleys and spindles are bent. The blades may also be dull if you’ve been using them for quite some time.


To know if your zero-turn mower has a pump or wheel motor issue, plug the mower off, remove the fittings, and disconnect the motor. Then, try pulling the lever forward. If it pulls all the way, the pump is likely faulty because it’s not doing its job of stalling the engine. 

If it doesn’t pull all the way, the pump is OK, and the problem is likely with the wheel motor.

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