5 Most Reported John Deere Z950R Problems + Effective Fixes

John Deere’s commercial-grade zero-turn mowers are popular among homeowners and professional landscapers. If you’re a fan of the JD Z900 Series, the Z950R can be a worthwhile investment.

This mower is powerful, ultra-durable, and efficient. It has a 27HP v-twin engine and a hydrostatic transmission that provide years of service. But like other zero turns, the John Deere Z950R is prone to several issues. The most common John Deere Z950R problems are PTO failure, starting difficulties, transmission issues, uneven cuts, and low engine oil pressure.

Do you own a problematic JD Z950R? Read on to understand your mower’s issues and effective fixes.

Starting Difficulties

Any mower can have starting difficulties from time to time. So, does your Z950R fail to start or require several attempts before starting? If so, examine the fuel system, battery, and spark plug.

Often, starting difficulties with this zero turn result from the following:

  • Insufficient fuel
  • Clogged fuel lines
  • Failing battery
  • Bad spark plug

Effective Fixes:

Check the tank to ensure it has sufficient fuel. If the fuel looks dark or cloudy, it might be dirty or contaminated. Drain this fuel and add fresh fuel.

Dirty or contaminated fuel clogs up the lines with debris or residues. Clean the lines with compressed air and replace the fuel filter. A fuel additive will also help clean the lines and keep the fuel healthy.

If the mower doesn’t start after fixing the fuel line, examine the battery for defects. Clean any corroded terminals and tighten the connections. Recharge the battery if low. If the battery fails to accept a charge, replace it.

Probe the spark plug and replace it if broken or damaged. If the plug is loose, secure it as required.

PTO Failure

Most JD Z950R users claim that the PTO fails to engage after turning on the switch. This problem occurs after using the mower for an extended period.

The PTO can’t engage due to the following:

  • Worn-out PTO switch
  • Defective fuse
  • Insufficient transmission fluid
  • Damaged or loose connections


The PTO switch can succumb to wear and tear over time and malfunction. Examine the switch for physical damage or test it with a multimeter. If the switch is defective, replace it.

Then locate the PTO fuse. A blown or burned fuse can prevent the PTO from engaging. Replace the fuse if necessary.

The sub-harness and connections in the PTO clutch could be damaged or loose. Tighten the connection and replace a damaged sub-harness.

If none of the above works, check the transmission fluid level. Low transmission oil stalls the PTO clutch engagement. Refill the reservoir if the fluid level is low.

Hydrostatic Transmission Issues

One of the most common John Deere Z950R problems is malfunctioning hydrostatic transmission. While this system offers precise control, smooth operations, and reliable performance, it can encounter several issues over time.

The most common reasons for the hydrostatic transmission acting up are:

  • Insufficient hydrostatic transmission fluid
  • Malfunctioning drive belt
  • Air in the system
  • Faulty pulleys

Effective Fixes:

Start by checking the fluid level in the reservoir. Refill the reservoir if the level is low. You can also check for leaking parts and fix them. If the existing fluid is bad or contaminated, change it.

Then examine the drive belt and pay attention to signs of misalignment, wear, or damage. Align the belt and ensure it’s tight. If the belt looks worn or damaged, replace it. While still at the belt, inspect the idler pulley for signs of damage. Replace a damaged pulley and lubricate the tension arm.

Cavitation (air in the system) can also make the hydrostatic transmission act up. Purge the system to remove the air if necessary.

Low Engine Oil Pressure

Engine oil in your JD Z950R lubricates moving parts to prolong the engine’s lifespan. The oil requires sufficient pressure to circulate the engine and do its job.

Unfortunately, some Z950R owners have encountered issues with the engine oil pressure. They claim their mowers give a warning code 2-7, bog down, and shut off. This warning code indicates a low engine oil pressure problem.

When this code appears while mowing, the PTO might get disengaged.

Low engine oil pressure in this mower can result from the following:

  • Low oil level
  • Clogged oil filter
  • Malfunctioning oil pressure sensor
  • Defective oil pressure sensor wiring

Effective Fixes:

Before checking for faulty components, ensure your mower has sufficient engine oil. Refill the reservoir as the manual recommends if the oil level is low. 

Drain the oil and add fresh engine oil if it is dirty or contaminated.

Then locate the oil filter and inspect it for clogs. A clogged filter will reduce oil flow and pressure. And like most John Deere Z950R problems, neglecting routine maintenance can cause the filter to get clogged. So, change the filter if it looks dirty or clogged.

If the low oil pressure issue persists, examine the oil pressure sensor to see if it’s functional. A malfunctioning oil pressure sensor can cause the ECM to throw the warning code 2-7. When this happens, your mower might bog down and shut off.

Use your multimeter to test the sensor. You can follow the owner’s manual to test and interpret the results. If the sensor is faulty, replace it.

Examine the oil pressure sensor wiring for signs of defects. Ensure the connections are tight and secure. If the wire harness looks damaged or frayed, replace it. 

Uneven Cuts

Another common issue with this zero turn is uneven cuts. Your zero turn might leave your lawn with unevenly cut grass or spots with uncut grass.

The uneven cut problem can result from the following:

  • Wrong deck level
  • Dull blades
  • Damaged or bent blades
  • Uneven tire pressure


Before engaging the blades, always adjust the deck’s position as instructed in the owner’s manual. Then examine the blades to see if they’re dull or bent. Straighten and sharpen the blades with blade sharpening and balancing tools.

If the blades look worn or damaged beyond repair, replace them. Check the tires to ensure they have equal pressure. You can deflate or inflate them to meet the manufacturer-recommended psi.

John Deere Z950R problems

Final Thoughts

While the Z950R encounters problems occasionally, it’s a reliable mower for residential and commercial use. John Deere Z950R problems are common in other zero turns and require basic skills to resolve them.

If your mower has one of these problems, deal with it as illustrated above. You can also seek help or advice from an experienced mechanic. With regular maintenance and proper handling, your JD Z950R will remain in prime condition for years.