6 Most Common John Deere Z915E Problems And Quick Fixes

John Deere Z915E lawnmowers are durable and have 11.5-gallon fuel tanks, allowing them to mow for long durations without interruptions. Despite their outstanding features, these mowers are reported to have several drawbacks. So, what are the most common John Deere Z915E issues? The most common John Deere Z915E problems are engine issues, problematic starts, hydraulic pump complications, steering issues, rough cuts, and transmission problems.

Read on as we describe frequent 915E John Deere problems and their fixes.

Starting Problems

Dirty or damaged carburetors, faulty chokes, clogged fuel filters, damaged spark plugs, stale fuel, corroded, low engine oil viscosity, and corroded connections are the primary causes of John Deere Z915E starting problems.

Dirty carburetors hinder the flow of fuel/air mixture necessary for starting the mower. An imbalance in the air and fuel ratio results in starting difficulties. Regularly clean your mower’s carburetor to avoid these issues.

A faulty choke allows excess fuel to flow into the engine, leading to overflooding and hard starts. Regularly monitor these elements and replace them if damaged.

Clogged filters hinder smooth fuel flow to the engine, causing hard starts. Regularly clean your mower’s fuel filters to avoid plugging or clogging.

John Deere Z915E mowers’ engines depend on a spark from the spark plugs to ignite and start. These mower elements easily break and malfunction after prolonged use. Monitor them closely and replace them at first sight of aging. Switching spark plugs annually is advisable to maintain your mower’s effectiveness.

Fuel absorbs water from its surroundings and reduces its volatility with time. Stale fuel is incapable of providing adequate energy to power the engine. It also corrodes engine parts, which may require replacement. To fix this problem, flush out all the old fuel and replace it with new gas.

To keep your John Deere Z915E mower’s engine healthy and avoid hard starts, change the fuel after every twenty to fifty hours.

Loose and corroded connections hinder smooth electricity flow through the mower’s system. Regularly clean dirty terminals and cables to curb this problem. You should always check all connections and tighten loose ones before setting off.

Low-viscosity engine oils take a long time to reach the engine, leading to hard starts. Stick to the recommended oil with the correct viscosity to avoid this inconvenience.

Transmission Problems

John Deere Z915E mowers feature hydrostatic transmission systems, which depend on the hydraulic pump to transform the mower’s electric energy into mechanical power. These systems’ problems result from aerated hydraulic fluid and mechanical hydraulic issues.

To fix John Deere Z915E transmission problems, first, bleed the hydraulic system to eliminate all the excess air. It’s advisable to bleed or purge the system if it’s stayed idle for a while. Air fills up the pipes and lines when the mower isn’t in motion.

Low hydraulic fluids strain the transmission system. Check for any damaged transmission and hydraulic parts that may be leaking and replace them with new ones. It would be best to refill the hydraulic fluid to the recommended level.

Engine Issues

The leading John Deere Z915E engine problems are overheating and knocking.


John Deere Z915E engines might overheat due to the following:

  • Plugged air intake screens
  • Clogged cooling fins
  • Insufficient engine oil

Air intake screens are responsible for letting in cold air to cool down the engine’s high temperatures. These mower components get plugged from dirt and debris build-up. Clean them regularly for cool, comfortable rides.

Cooling fins pull heat away from the engine. The engine maintains most of the heat when faulty, leading to overheating. Replace damaged cooling fins to solve these John Deere Z915E problems.

Low engine oil doesn’t lubricate the engine parts sufficiently, causing them to overwork and produce excess heat. Regularly monitor your mower’s engine oil levels. If depleted, refill the oil pan to the recommended level.


Your mower’s engine might produce a knocking sound due to carbon deposits, low engine speed, or low-octane fuel.

Carbon molecules, produced during combustion, clog the engine parts involved in this process. This clog reduces the cylinder’s volume and increases the compression levels, making a knocking sound.

Low engine speed allows the air and fuel mixture to ignite prematurely. This means the combination explodes instead of burning, producing a knocking sound. To maintain your mower’s engine speed, stick to the right motor oil that keeps the engine clean and protects engine parts from wear and tear.

Low-octane fuels also promote premature ignition. Stick to the recommended high-octane fuels to avoid this issue.

Hydraulic Pump Problems

Most John Deere Z915E users complain about hydraulic pump complications. Aeration is the leading cause of this issue. Excess air in place of oil reduces the hydraulic pump’s pressure production. Limited pressure results in low power.

To curb hydraulic pump issues, you should check for damaged parts that allow air into the system and repair or fix them immediately. It’s also advisable to purge the system regularly to avoid the chances of extreme aeration.

Stick to fuel pumps that meet the California Air Resources Board standards, as they are unlikely to let air into the system.

Low oil levels increase the system’s air concentration. Regularly refill the oil to the recommended level to solve these issues.

Problematic Steering

John Deere Z915E mowers sometimes experience hard or wobbly steering. The leading cause of difficult steering is wrong tire pressure. Uneven tire pressure delays the wheels’ response, leading to stiff steering. Low pressure increases the lateral and forward drag, making steering difficult.

Always confirm that all the tires have equal tire pressure before setting off. If deflated, inflate the tires according to the mower’s PSI recommendations.

Gears malfunction due to age, causing difficult steering. Check on these components regularly and replace them with new ones if they show signs of wearing out.

Spindles transfer movements from the steering wheel to the mower’s front wheels. When faulty, they hinder the transfer of movements, resulting in hard or stiff steering. To fix these John Deere Z915E problems for good, replace damaged spindles.

Rough Cuts

Uneven cuts result from unleveled decks, dull blades, or unequal tire pressure. Unlevelled decks tip on one side, leading to uneven cuts.

Park the mower on flat ground and adjust the decks until both sides are aligned to fix this problem. Ensure you turn the mower off before handling the deck to avoid accidents.

Dull blades rip the top part of the grass instead of cutting, resulting in an ugly raggedy look. Regularly sharpen your mower’s blades to curb these issues.

Uneven tire pressure results in a bumpy ride, affecting the mower’s cutting efficiency. Always ensure all the tires have equal pressure.

Are John Deere Z915E Problems a Deal Breaker?

John Deere Z915E problems aren’t a deal breaker. These lawnmowers have more pros than cons, thanks to their outstanding features. What’s more, this article explains the fixes you may need to repair your mower.