Used Lawn Mower Testing Guide 2026

Overview: Evaluating Used Lawn Mowers

Lawn mowers are among the most commonly purchased used outdoor power equipment, and for good reason. A quality mower can last 10-15 years with proper maintenance, and used units often sell for 40-60% of retail price. However, lawn mowers are also prone to neglect—sitting through winters with stale gas, running on dirty oil, or being stored outside exposed to elements. Understanding what separates a well-maintained bargain from a money pit requires knowing exactly what to inspect and test.

The used mower market has shifted significantly with the rise of battery-powered electric mowers. Many homeowners who purchased gas mowers are now selling them in favor of quieter, lower-maintenance electric options. This creates opportunities to find premium gas mowers at excellent prices. Meanwhile, early-generation electric mowers are entering the used market as buyers upgrade to newer models with longer battery life and improved power.

Essential Tools for Mower Testing

Gas Engine Testing

For gas-powered mowers, the engine is the most critical and expensive component to evaluate. Small engines (typically Briggs & Stratton, Honda, or Kohler) are remarkably durable when maintained but can develop expensive problems when neglected. A thorough cold-start test reveals more about engine health than any visual inspection.

Pre-Start Inspection

Before attempting to start the engine, perform these checks:

• Oil Level and Condition: Pull the dipstick and check both level and color. Oil should be between min and max marks and appear amber to light brown. Black, gritty oil indicates poor maintenance. Milky oil suggests head gasket problems or water intrusion.
• Air Filter: Remove and inspect the air filter. Heavy dirt or oil saturation suggests the engine has been running rich or pulling debris through the filter. A clean filter in an otherwise dirty mower might indicate recent seller prep.
• Fuel System: Look in the gas tank with a flashlight. Check for rust, debris, or old varnished fuel. Smell the gas—stale fuel has a distinct sour smell compared to fresh gasoline.
• Spark Plug: If possible, remove the spark plug. A tan or light gray electrode indicates good combustion. Black, sooty deposits suggest running rich. White or blistered electrodes indicate overheating.

Cold Start Test

Ask the seller to leave the mower cold (not started for at least 2-4 hours, preferably overnight). A cold engine reveals problems that disappear once warmed up. Observe the starting process carefully:

• Number of Pulls: A healthy engine should start within 3-5 pulls with fresh gas and proper choke use. More than 8-10 pulls suggests carburetor, compression, or ignition issues.
• Initial Exhaust: A puff of blue smoke on first start can be normal (oil seeping past rings overnight). Continuous blue smoke indicates worn rings or valve guides.
• White Smoke: Persistent white smoke suggests head gasket failure or water in the combustion chamber—serious problems.
• Idle Quality: Once started, the engine should settle into a steady idle without surging, hunting, or dying. Rough idle usually indicates carburetor problems.

Under-Load Testing

An engine that idles well might struggle under the load of actually cutting grass. If possible, test the mower on actual lawn:

• Listen for the engine to maintain consistent RPM when the blade engages
• Mow through some taller grass to load the engine—it shouldn't bog down excessively
• Check for smoke during operation, not just at startup
• After 10-15 minutes of operation, verify oil level hasn't dropped significantly (consumption)

Electric and Battery Mower Testing

Battery-powered mowers have fewer mechanical components than gas mowers but introduce different concerns—primarily battery degradation. Lithium-ion batteries lose capacity over time and with use, and replacement batteries can cost $200-$500 depending on the model. Understanding how to evaluate battery health is essential for used electric mower purchases.

Battery Health Assessment

Battery degradation is the primary concern with used electric mowers. Unfortunately, precise capacity testing requires specialized equipment, but you can make reasonable assessments:

• Age: Lithium batteries typically retain 80% capacity after 300-500 charge cycles or 3-5 years. Ask when the mower was purchased and estimate usage frequency.
• Charge Test: Ask the seller to fully charge the battery before your visit. Note the charge level indicator and whether it shows full capacity.
• Runtime Test: If possible, mow a measured area and compare to manufacturer specifications. A battery delivering half the rated runtime indicates significant degradation.
• Charge Time: A battery that charges unusually quickly may have reduced capacity. A battery that won't reach full charge has definite problems.

Motor and Electronics

Electric motors are generally reliable, but listen for unusual sounds:

• Grinding or Scraping: May indicate bearing wear or blade interference
• Clicking or Stuttering: Could suggest motor controller issues
• Burning Smell: Indicates electrical problems—stop testing immediately
• Inconsistent Power: May be battery contacts, motor brushes (if applicable), or controller

Corded Electric Mowers

For corded electric mowers, inspect the cord thoroughly for cuts, exposed wires, or damaged insulation. Check the cord strain relief where it enters the motor housing. Verify the safety interlock (blade stops when handle lever is released) works reliably. These mowers are simpler but cord damage is both common and dangerous.

Blade Inspection

Mower blades are consumable items and should be evaluated as part of the overall purchase. While blades are relatively inexpensive to replace ($20-$50 for most mowers), severely damaged blades can indicate impacts that affected the crankshaft or spindle—much more serious issues.

Visual Blade Inspection

With the mower off, spark plug disconnected (for safety), and the mower tipped appropriately (see owner's manual for correct tipping direction to avoid oil flooding), examine the blade:

• Edge Condition: The cutting edge should be reasonably sharp without major nicks, gouges, or bent sections. Minor wear is normal; severe damage affects cut quality.
• Balance: Significant material missing from one side creates imbalance causing vibration, wear, and potential shaft damage.
• Bend Check: Sight down the blade from the end. It should be straight. Even minor bends create vibration and indicate impacts.
• Mounting Hardware: Check the blade bolt and adapter for damage, cross-threading, or wear.

Spindle and Crankshaft Check

Rock the blade by hand (with the engine off). There should be minimal play—slight movement is normal due to blade mounting tolerances, but significant wobble or play indicates:

• Bent Crankshaft: Common from striking solid objects. Causes vibration and eventual bearing failure. Expensive to repair.
• Worn Spindle Bearings: On riding mowers with separate spindles. Less critical but indicates heavy use.
• Loose Blade Adapter: Sometimes just needs tightening, but check for stripped threads or worn keyways.

Start the mower and observe it from a safe distance. Excessive vibration, especially that worsens at full throttle, suggests bent crankshaft or severely unbalanced blade. Some vibration is normal for single-cylinder engines, but violent shaking is problematic.

Deck Condition Assessment

The mower deck takes significant abuse from rocks, roots, and corrosion from grass clippings. While minor wear is expected, serious deck damage affects cut quality and can be expensive or impossible to repair on residential mowers.

Underside Inspection

The underside of the deck reveals the mower's true history. Use a flashlight and inspect:

• Rust and Corrosion: Surface rust is common and usually cosmetic. Deep, flaking rust that has eaten through the steel compromises structural integrity.
• Impact Damage: Dents and gouges from striking objects. Minor dents are normal; holes or tears require deck replacement.
• Grass Buildup: Heavy caked-on buildup suggests the mower wasn't cleaned regularly and may have additional corrosion underneath.
• Discharge Chute: Check the side or rear discharge area for damage, cracks, or missing parts.

Height Adjustment Mechanism

Test the deck height adjustment through its full range:

• Lever should move smoothly without excessive force
• Deck should lock positively at each height setting
• All four wheels should adjust together (on single-lever systems)
• Check that the deck sits level at each setting

Wheels and Axles

Spin each wheel and check for smooth rotation. Wobbling wheels indicate bent axles or worn bushings. Height adjustment gears inside the wheels wear out on some models—verify the adjuster actually changes wheel height, not just moves a lever.

Self-Propel System Testing

Self-propelled mowers add significant convenience but also add mechanical complexity that can fail. The drive system—whether front-wheel, rear-wheel, or all-wheel—requires careful evaluation. Drive repairs can be costly and DIY-unfriendly.

Drive Types and Their Issues

Testing the Drive System

With the engine running and blade disengaged (if possible):

• Engage the self-propel lever—the mower should move smoothly without jerking
• Check variable speed control if equipped—should provide smooth acceleration
• Test on flat ground and on a slope if available
• Listen for grinding, clicking, or unusual noises from the transmission
• Check that the mower stops promptly when releasing the drive lever

On belt-driven rear-wheel systems, a burning rubber smell or squealing indicates worn belts. On gear-driven front-wheel systems, stripped plastic gears inside the wheels are a common failure that causes loss of drive.

Riding Mower and Lawn Tractor Testing

Riding mowers and lawn tractors represent a significant investment even when buying used. These machines have more components to evaluate—hydrostatic transmissions, multiple spindles, and complex electrical systems add to the inspection requirements.

Transmission Evaluation

Most modern riding mowers use hydrostatic transmissions. These should provide smooth, infinite speed control in both forward and reverse:

• Smooth Operation: Jerky movement or hesitation suggests low fluid or internal wear
• Fluid Check: If accessible, check transmission fluid level and condition
• Hill Test: Drive up and down a slope—the mower should hold position without creeping
• Neutral: In neutral, the mower should roll freely (important for flat tires or dead batteries)

Deck and Spindle Inspection

Riding mower decks have 2-3 spindles, each with its own blade and bearings:

• With the deck lowered and engine off, grasp each blade and check for play
• Spin each blade by hand—it should rotate smoothly without roughness
• Listen to the spindles when running—grinding or squealing indicates bearing failure
• Check the belt for cracking, fraying, or glazing

Electrical System

Riding mowers have more complex electrical systems with safety interlocks:

• Battery: Should hold charge and start engine readily. Load test if possible.
• Charging: After running, battery voltage should increase (13.5-14.5V running)
• Safety Switches: Blade should not engage with no one in seat. Engine should stop if you leave seat with blade engaged (on most models)
• Lights: Check headlights if equipped—useful for evening mowing

Brand-Specific Testing Tips

Used Lawn Mower Pricing Guide

Used mower values vary significantly based on brand, type, and condition. Use this guide for baseline pricing:

Final Inspection Checklist

Use this interactive checklist during your in-person inspection: