Cub Cadet Rzt 42 Problems

Cub Cadet RZT 42 Problems: Troubleshooting Guide and Solutions

The Cub Cadet RZT 42 zero-turn mower offers excellent maneuverability and cutting performance for residential lawns, but like any mechanical equipment, it can develop problems over time. Owners of the Cub Cadet RZT 42 sometimes encounter issues with starting, movement, steering, and power transmission.

Understanding these common Cub Cadet RZT 42 problems can help you diagnose issues quickly and implement effective solutions, extending the lifespan of your investment and keeping your lawn looking pristine.

This comprehensive guide explores the most frequent problems, their causes, and practical troubleshooting steps to get your mower back in optimal condition.

Quick Takeaway

Regular maintenance prevents most common RZT 42 issues
Transmission problems often stem from lack of proper fluid levels
Steering issues typically relate to loose components or misalignment
Starting problems frequently involve electrical system faults
PTO engagement failures usually indicate worn clutch components

The Cub Cadet RZT 42 is generally a reliable zero-turn mower, but owners most commonly encounter issues with the transmission, steering system, starting mechanism, and PTO engagement. Most problems can be resolved through proper maintenance and timely replacement of worn components.

Common Cub Cadet RZT 42 Starting Problems

One of the most frustrating experiences for any Cub Cadet RZT 42 owner is when the mower refuses to start. These starting problems can stem from various causes, from simple fuel issues to more complex electrical faults.

Dead or Weak Battery

The battery is often the culprit when your Cub Cadet RZT 42 won’t start. A fully charged 12-volt battery is essential for proper starting. If your mower clicks but won’t turn over, it’s likely suffering from insufficient battery power.

How to diagnose:

Check battery terminals for corrosion or loose connections
Use a multimeter to test battery voltage (should read at least 12.4V)
Inspect for visible damage to battery casing

Solutions:

Clean battery terminals with a wire brush and reconnect securely
Charge the battery fully using a trickle charger
Replace the battery if it’s older than 3-4 years or fails to hold a charge

Most Cub Cadet batteries should last 2-3 years with proper maintenance, though environmental factors and usage patterns can affect lifespan.

Fuel System Issues

Another common starting problem relates to fuel delivery. Stale fuel, clogged fuel filters, or carburetor problems can prevent your RZT 42 from starting properly.

How to diagnose:

Check fuel level and quality (fuel shouldn’t smell sour or contain visible debris)
Inspect fuel filter for clogging
Look for fuel leaks around carburetor or fuel lines

Solutions:

Drain old fuel and replace with fresh gasoline
Replace fuel filter according to maintenance schedule
Clean carburetor or have it professionally serviced if it’s heavily clogged

It’s good practice to add fuel stabilizer when storing your mower for extended periods to prevent fuel degradation.

Faulty Safety Switches

The Cub Cadet RZT 42 has multiple safety switches that prevent starting under unsafe conditions. Malfunctioning switches can trigger false safety cutoffs.

How to diagnose:

Verify proper seating in the operator position
Check that the parking brake is engaged
Ensure PTO switch is in the OFF position
Test continuity of safety switches with a multimeter

Solutions:

Adjust switch positioning if misaligned
Clean switch contacts if dirty
Replace faulty safety switches

Remember that bypassing safety switches is dangerous and not recommended, even as a temporary solution.

Cub Cadet RZT 42 Transmission Problems

The hydrostatic transmission in the Cub Cadet RZT 42 is designed for smooth operation, but it can develop issues that affect movement and performance. Transmission problems are among the most commonly reported issues with these mowers.

Loss of Power or Slow Movement

If your RZT 42 seems to lack power or moves slower than usual, the transmission is likely the source of the issue.

How to diagnose:

Check for unusual noise during operation
Observe if the problem occurs in forward, reverse, or both
Test if the issue is worse under load or on inclines

Solutions:

Check and top up hydrostatic transmission fluid
Release the transmission bypass valves and reset
Allow the transmission to cool if overheated
Purge air from the hydraulic system following manufacturer guidelines

Transmission Fluid Leaks

Leaking transmission fluid not only creates a mess but also reduces the effectiveness of your hydrostatic drive system.

How to diagnose:

Look for puddles or spots under the mower after parking
Check transmission case seals and fittings
Inspect hoses for cracks or damage

Solutions:

Tighten loose fittings
Replace damaged seals
Repair or replace cracked hoses
Maintain proper fluid levels

Uneven Movement or Pulling to One Side

If your Cub Cadet RZT 42 doesn’t track straight or pulls to one side, the transmission system may need adjustment.

How to diagnose:

Test mower on a level surface
Check tire pressure on both drive wheels
Verify that both transmission drive systems engage equally

Solutions:

Equalize tire pressure according to specifications
Adjust the tracking control system
Clean debris from transmission components
Check for worn bearings in drive system

Regular maintenance of the transmission system can prevent most serious problems. Changing the hydraulic fluid according to the maintenance schedule (typically every 200 hours) helps extend transmission life significantly.

Steering Problems with the Cub Cadet RZT 42

The steering system on the RZT 42 provides its zero-turn capability, but various steering problems can develop over time that affect maneuverability and control.

Loose or Stiff Steering

One common complaint about the Cub Cadet RZT 42 is that the steering becomes either too loose or too difficult to operate.

How to diagnose:

Check for excessive play in the steering levers
Test if both steering levers have the same resistance
Inspect steering components for wear or damage

Solutions:

Adjust steering lever tension according to manual specifications
Lubricate pivot points and steering components
Replace worn bushings or bearings
Tighten loose hardware in the steering system

Steering Alignment Issues

Improper alignment causes the mower to veer off course or require constant correction during operation.

How to diagnose:

Test if the mower tracks straight with hands off the controls
Check for bent steering components
Verify that wheel speeds are equal when controls are in neutral

Solutions:

Adjust the tracking control rod
Check for proper wheel alignment
Replace any bent or damaged steering components
Calibrate the neutral position of the control levers

Control Lever Damping Problems

The dampers that provide resistance in the steering control levers can wear out or lose effectiveness.

How to diagnose:

Test if levers return to neutral position properly
Check for smooth lever movement throughout range
Inspect damper units for leaks or damage

Solutions:

Adjust damper tension if possible
Replace worn or damaged dampers
Lubricate control lever pivot points
Clean debris from damper mechanisms

Proper maintenance of the steering system not only improves control but also contributes to a more comfortable mowing experience and reduces operator fatigue during long mowing sessions.

PTO and Cutting Deck Problems

The Power Take-Off (PTO) system engages the cutting blades on your Cub Cadet RZT 42. PTO problems can prevent blade engagement or cause unexpected shutdowns during mowing.

PTO Won’t Engage

If the blades don’t spin when you engage the PTO switch, several components could be at fault.

How to diagnose:

Listen for clicking sound when engaging PTO
Check for visible damage to PTO clutch
Verify proper electrical connections to PTO system

Solutions:

Test PTO clutch with multimeter for proper resistance
Clean connections on PTO wiring harness
Adjust PTO clutch air gap per specifications
Replace worn PTO clutch assembly if necessary

Mower Shuts Off When PTO Is Engaged

A common complaint is that the Cub Cadet RZT 42 engine dies when attempting to engage the cutting blades.

How to diagnose:

Check if problem occurs consistently or intermittently
Verify engine RPM before engaging PTO
Test battery voltage under load

Solutions:

Engage PTO at lower engine RPM then increase speed
Test and replace weak battery if needed
Clean or replace air filter to improve engine performance
Check for excessive load or jammed cutting deck

Uneven Cutting or Vibration

Problems with the cutting deck can result in poor cutting quality and excessive vibration.

How to diagnose:

Inspect blades for damage or uneven wear
Check deck level from side to side and front to back
Look for bent spindles or loose components

Solutions:

Replace or sharpen damaged blades
Level deck according to manual specifications
Tighten all deck hardware and spindle assemblies
Clean accumulated grass and debris from underside of deck

Regular inspection and maintenance of the PTO system and cutting deck will help ensure consistent cutting performance and prevent more serious mechanical failures.

Electrical System Failures

The electrical system powers many critical functions on the Cub Cadet RZT 42, and electrical problems can manifest in various ways.

Intermittent Operation or Shutdown

If your RZT 42 runs for a while then dies unexpectedly, electrical issues are often the cause.

How to diagnose:

Check if problem occurs after mower warms up
Look for loose or corroded electrical connections
Test ignition module for proper operation

Solutions:

Clean and secure all electrical connections
Check for damaged wiring and repair as needed
Test and replace faulty ignition components
Verify proper operation of safety switches

Dashboard Indicator Problems

Malfunctioning indicators or gauges can provide incorrect information or fail to warn of potential issues.

How to diagnose:

Verify if all dashboard indicators light up during startup
Check for consistent readings on gauges
Test wiring connections to dashboard components

Solutions:

Replace burned-out indicator bulbs or LEDs
Clean electrical contacts to dashboard
Check fuses related to instrumentation
Replace faulty sensors or sending units

Charging System Issues

Problems with the charging system can lead to repeated battery failures and starting difficulties.

How to diagnose:

Test voltage at battery terminals with engine running (should be 13.5-14.5V)
Check alternator/stator output
Inspect charging system wiring for damage

Solutions:

Tighten or replace loose/damaged connections
Clean corrosion from charging system components
Replace faulty voltage regulator
Rebuild or replace alternator/stator if output is insufficient

Modern Cub Cadet RZT models have increasingly complex electrical systems, making proper diagnosis and repair more challenging but also more critical for reliable operation.

The engine is the heart of your Cub Cadet RZT 42, and various engine problems can affect performance and reliability.

Loss of Power During Operation

If your mower loses power during use, especially under load, several engine-related issues could be responsible.

How to diagnose:

Monitor for unusual engine sounds or smoke
Check if power loss occurs gradually or suddenly
Observe operating temperature and conditions

Solutions:

Clean or replace air filter
Replace fuel filter and verify fuel quality
Check spark plug condition and gap
Clean cooling fins to prevent overheating
Test compression to check for internal engine wear

Excessive Smoke or Unusual Noise

Smoke or abnormal sounds often indicate specific engine problems that need addressing.

How to diagnose:

Note smoke color (white, black, or blue)
Identify when noise occurs (startup, idle, or under load)
Check oil level and condition

Solutions:

For black smoke: clean air filter, adjust carburetor
For blue smoke: check for oil burning issues, worn piston rings
For white smoke: look for coolant leaks or moisture in fuel
For knocking sounds: check for loose components or internal damage
For rattling: tighten external engine components

Overheating Issues

An overheating engine can cause performance problems and potentially lead to serious damage.

How to diagnose:

Feel for excessive heat after shutdown (use caution!)
Check for restricted airflow around engine
Monitor operating conditions (heavy loads, tall grass)

Solutions:

Clean cooling fins and air intake screens
Ensure proper oil level and condition
Avoid operating in extremely hot conditions or in overly tall grass
Check for proper governor operation
Service or replace cooling system components if equipped

The engine in your Cub Cadet RZT 42 typically has a longer lifespan than many of the wear components, but proper maintenance is essential for maximizing reliability and performance.

Preventive Maintenance to Avoid Common Problems

Many Cub Cadet RZT 42 problems can be prevented through proper maintenance practices. Establishing a regular maintenance schedule extends equipment life and reduces downtime.

Regular Maintenance Schedule

Following a consistent maintenance routine prevents many common issues before they develop.

Daily checks:

Inspect fluid levels (oil, fuel, hydraulic fluid)
Check tire pressure
Remove debris from engine cooling areas and deck
Look for loose fasteners or components

Seasonal maintenance:

Change engine oil and filter
Replace air filter
Sharpen or replace blades
Lubricate moving parts and pivot points
Check belt condition and tension

Annual maintenance:

Replace fuel filter
Replace spark plug
Clean fuel system
Check battery condition
Inspect electrical connections

Storage Preparation

Proper storage during off-seasons prevents many starting and performance problems when you’re ready to use your mower again.

Steps for proper storage:

Clean mower thoroughly, especially the underside of the deck
Add fuel stabilizer to fresh gas or drain fuel system completely
Remove battery and store in cool, dry location
Lubricate all pivot points and exposed metal
Store in dry, covered location

When to Seek Professional Help

While many maintenance tasks can be performed by owners, some situations warrant professional assistance.

Consider professional service for:

Major transmission repairs
Internal engine problems
Complex electrical system diagnostics
PTO clutch replacement
Extensive structural damage

Regular dealer service can also help identify potential issues before they become serious problems, potentially saving significant repair costs in the long run.

FAQ About Cub Cadet RZT 42 Problems

What does RZT stand for on Cub Cadet mowers?

RZT stands for “Residential Zero Turn.” This designation indicates that the mower is designed with zero-turn capability for residential rather than commercial use. The zero-turn functionality allows for excellent maneuverability around obstacles and tight spaces in typical home lawns.

Why does my Cub Cadet zero-turn shut off when I engage the blades?

When your Cub Cadet RZT 42 shuts off upon blade engagement, it’s typically due to excessive load on the engine, a weak battery, faulty PTO clutch, or problems with the safety interlock system. Try engaging the PTO at lower RPM, check battery voltage, and ensure the deck is free from obstructions that might cause excessive drag on the blades.

Why is my Cub Cadet RZT 42 slowing down during operation?

Gradual slowing during operation usually indicates transmission issues, such as low hydraulic fluid, overheating transmission, air in the hydraulic system, or worn hydraulic pumps. Regular transmission maintenance, including fluid changes and system purging, can prevent most of these problems and restore proper speed.

Is a Cub Cadet zero-turn mower good quality?

Cub Cadet zero-turn mowers, including the RZT 42, are generally considered good quality residential-grade machines with solid construction and reliable performance when properly maintained. They offer excellent value for homeowners with medium to large lawns, though they may not have the durability of commercial-grade models for daily professional use.

How long should a Cub Cadet battery last?

A Cub Cadet battery typically lasts between 2-4 years, depending on usage patterns, storage conditions, and maintenance. Regular charging during off-seasons, cleaning terminals, and ensuring the charging system works properly will maximize battery life. Batteries that are consistently discharged completely will have shorter lifespans.

What is the top speed of the Cub Cadet RZT 42 zero-turn?

The Cub Cadet RZT 42 has a maximum forward speed of approximately 7 mph (11.3 km/h) and a reverse speed of about 3.5 mph (5.6 km/h). These speeds are sufficient for residential mowing while maintaining safe operation. Actual speed may vary slightly based on model year and specific configuration.

Why does my Cub Cadet keep shutting off unexpectedly?

Unexpected shutdowns can result from various issues including safety switch malfunctions, fuel delivery problems, overheating, ignition system faults, or low oil pressure triggering shutdown protection. Systematic troubleshooting of these systems will usually identify the specific cause of intermittent shutdowns.

Final Thoughts

The Cub Cadet RZT 42 is a capable and reliable zero-turn mower for residential use, but like all mechanical equipment, it can develop problems over time. Most Cub Cadet RZT 42 problems can be resolved through proper diagnosis and timely maintenance. By understanding common issues with starting, transmission, steering, and electrical systems, owners can often perform simple repairs themselves or know when to seek professional assistance.

Regular maintenance remains the best strategy for preventing problems and extending the life of your investment. Following the manufacturer’s recommended service schedule, using high-quality replacement parts, and addressing minor issues before they escalate will help ensure your Cub Cadet RZT 42 provides years of dependable lawn care service.

Whether you’re troubleshooting a specific issue or simply wanting to maintain your mower in top condition, this guide provides a solid foundation for understanding the common problems and solutions for the Cub Cadet RZT 42. With proper care and timely intervention, most owners can overcome typical challenges and enjoy the convenience and performance that these popular zero-turn mowers offer.