Common problems and repair guides for small engines
Small engines — the Briggs & Stratton, Honda, Kohler, and Tecumseh power plants found in mowers, generators, pressure washers, and more — all share the same core systems: fuel, spark, air, and compression. When you understand how to diagnose those four systems, you can fix almost any small engine problem regardless of the equipment it powers. Our small engine guides break down each system with practical, field-tested troubleshooting steps.
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Polaris Ranger 570 Belt Squealing — Mechanical Diagnosis
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48 repair guides found
A squealing belt on a Polaris Ranger 570 is almost always a sign of clutch glazing, improper engagement, or water intrusion in the CVT housing. Constant low-speed driving or excessive high-load towing causes excessive heat that crystallizes the belt rubber, leading to friction loss and that characteristic high-pitched whine. While a replacement belt is a common fix, you must address the underlying cause to prevent premature failure of the new component.
First, verify the kill switch is in the 'Run' position and check for a strong blue spark using a gap tester set to 1/4 inch. If spark is present, ensure the fuel pump (on EFI models) primes for 2 seconds or the carburetor bowl has fresh fuel. On Honda TRX500 engines, the most common 'hidden' cause for a no-start condition is tight intake valves preventing cold compression; verify clearance is exactly .006 inches.
Engine surging is almost always caused by a restricted fuel flow or a dirty carburetor. Start by checking your fuel quality and replacing the fuel filter before attempting to clean or replace the carburetor.
On a Honda GCV160, the most common reason it turns over but won't fire is a failed auto-choke wax motor or a clogged pilot jet in the carburetor. First, verify the choke plate is fully closed when cold; if it is open, the engine won't draw enough fuel to ignite. If the choke is working, use a shot of carburetor cleaner in the intake to confirm a fuel delivery issue, then proceed to clean the main and pilot jets.
If your Honda GXV160 cranks but won't fire, the issue is almost certainly a fuel delivery blockage or a fouled spark plug. Start by performing a 'spray test' by injecting a small amount of carburetor cleaner into the intake; if it fires briefly, you have a confirmed fuel starvation issue. Focus your efforts on cleaning the pilot jet and main jet, as these are the most common failure points on this commercial-grade engine.
The most common reason a Honda HRX217 pulls but won't fire is a clogged pilot jet in the carburetor or a failed auto-choke wax element. First, ensure the fuel shut-off valve is turned to the ON position and the fuel is fresh; then, perform a 'shot test' by spraying carburetor cleaner into the air intake. If the engine fires briefly on the spray, the issue is fuel delivery, specifically the carburetor or the auto-choke linkage which often sticks due to debris.
On the 2017 Honda Pioneer 700-4, the fuel pump relay is located in the main fuse/relay box under the hood. If the engine cranks but won't fire, first verify the fuel pump primes for 2 seconds when the key is turned to 'ON'. Use a multimeter to check for 12V at the fuel pump connector; if power is present but the pump is silent, the pump module is likely failed.
On the fuel-injected Honda Pioneer 700 (SXS700), the most common causes for cranking without starting are a fouled NGK BKR6E-11 spark plug or a failed fuel pump. First, listen for the 2-second fuel pump prime when the key is turned to 'ON'; if silent, check the 10A fuel pump fuse and relay. If the pump primes, verify spark and check for stored PGM-FI fault codes via the dashboard MIL blink codes.
Engine surging usually indicates a fuel delivery problem caused by a dirty carburetor or contaminated fuel. Start by cleaning the carburetor passages and replacing old gasoline to restore smooth performance.
Engine backfiring on startup is typically caused by ignition timing issues, a sheared flywheel key, or old fuel causing poor combustion. Start by inspecting your spark plug for wear and replacing the fuel if it has been sitting for more than a month.
Engine surging on a Kohler Courage is almost always caused by a restricted fuel flow or a dirty carburetor. Start by checking for old fuel and replacing the fuel filter, then clean the carburetor to restore smooth performance.
On the fuel-injected 2021 Honda TRX520, first listen for the fuel pump's 2-second 'prime' hum when the key is turned to 'ON'; if silent, check the 10A fuel pump fuse and the Bank Angle Sensor. Verify the engine stop switch is in the 'RUN' position and the neutral light is illuminated, as the EFI logic requires these inputs to fire the injector. If the engine has spark but won't fire, the most likely culprit is a clogged fuel injector or degraded fuel within the high-pressure fuel line.
A weak crank on a 2016 Exmark Quest despite a new battery is almost always caused by excessive electrical resistance in the starting circuit or an issue with the engine's compression release. High-resistance connections at the ground strap or solenoid cause voltage drop, while a failed automatic compression release (ACR) makes the engine feel like it is hydrolocked. Systematically check voltage drop across the starter cable path before diving into the engine internals.
A Honda GX200 that starts and then dies is almost always due to a fuel supply issue or a clogged air filter. The most likely culprit is a dirty carburetor preventing steady fuel flow or old, stale gasoline.
The Honda Foreman 520 may not be starting due to fuel delivery issues or ignition failure. Start with checking the fuel system and spark plug condition to identify the specific cause.
On the Honda Foreman 520 (TRX520, 2020–2024), a no-crank is most often a discharged or high-resistance battery — not a bad starter. First confirm the green 'N' light is on and the handlebar kill switch is set to 'Run'. Load-test the battery: it must hold above 10.5V while you press the start button. If you hear a click but the engine won't turn, clean and tighten the 10mm battery terminals and the 30A main-fuse connections under the seat before condemning the solenoid or starter motor.
A clogged spark arrestor screen restricts exhaust flow, causing significant power loss, engine bogging under load, and overheating. To diagnose, remove the screen from the muffler outlet and inspect for carbon buildup or physical damage. If the screen is intact, clean it with a non-synthetic wire brush; if it is torn or heavily clogged, replace it immediately to restore engine performance.
A clicking sound when trying to start an ATV almost always indicates a low battery or a poor electrical connection. Start by charging the battery or checking the tightness of your terminal cables before suspecting a bad starter motor.
On a Briggs & Stratton 675 series engine, first verify the safety brake lever is fully engaged to pull the ground wire away from the ignition coil. Perform a 'dry fire' test by spraying carburetor cleaner into the air intake; if it starts briefly, the main jet (often the carburetor bowl nut) is clogged with ethanol residue. If there is no fire at all, check for a sheared flywheel key, which is a common failure point after hitting a solid object, throwing the ignition timing out of sync.
If your electric pressure washer is completely dead, first test the GFCI plug reset button and verify power at the outlet. If the unit cycles (starts/stops) while the trigger is released, you have a downstream water leak in the gun, hose, or pump seals causing a pressure drop. Always disconnect power before inspecting internal components to avoid electrical shock.
On a Craftsman YT3000, the first things to check are the 20-amp fuse located behind the dash or near the battery, and ensure the PTO lever is fully disengaged. Use a multimeter to verify 12.6V at the battery; if the solenoid doesn't click when the key is turned, the safety circuit (brake switch or PTO switch) is likely preventing the signal from reaching the starter. You can quickly test the starter motor by jumping the two large terminals on the solenoid with a screwdriver to see if it turns over.
The arcing at the positive cable combined with a clicking solenoid usually indicates a high-resistance short or a mechanical lock in the engine, commonly hydrolock on the Kohler 7000 series. First, remove the spark plugs and attempt to rotate the engine by hand to ensure it isn't full of fuel or seized. If the engine rotates freely, the arcing suggests the positive cable insulation has rubbed through against the frame or the 'new' starter has an internal short to its casing.
Engine surging, also known as 'hunting,' is almost always caused by a lean air-fuel mixture or a binding governor system. On Briggs & Stratton engines, this usually points to a partially clogged pilot (idle) jet or a vacuum leak at the intake manifold gaskets. First, check for air leaks by spraying carb cleaner around the intake while the engine runs; if the RPM smooths out, you've found a leak that needs a new gasket.
On the Kawasaki Mule Pro FXT (812cc engine), first verify the fuel pump is priming by listening for a 2-second hum from the fuel tank when the key is turned to 'ON.' If silent, check the 'Main' and 'EFI' relays in the fuse box under the front hood. If the pump primes but it won't fire, the most common failure point is fouled NGK BKR6E spark plugs or a failed crankshaft position sensor (CKP).
Belt squeal on a Kawasaki Mule Pro FXT is typically caused by a glazed CVT belt or contaminated clutch sheaves. Start by removing the CVT cover to inspect the belt width (service limit is 28.6mm) and check for 'hour-glassing' or shiny edges. If the belt is intact, use a Scotch-Brite pad and brake cleaner to remove rubber deposits from the aluminum sheave faces and blow out the clutches with compressed air to remove trapped dust.
On the fuel-injected Honda Rancher 420 (TRX420), first verify if the fuel pump 'primes' with a 2-second hum when the key is turned to ON; if silent, the issue is likely the fuel pump relay or the pump itself. Next, perform a spark test using an NGK BKR5E-11 plug to rule out ignition coil failure. Because these are PGM-FI machines, a common hidden culprit is a tripped Bank Angle Sensor or a clogged fuel injector due to stale ethanol fuel.
The most common reason a chainsaw cover won't go back on is that the chain brake was engaged while the cover was removed, causing the internal brake band to contract. To fix this, you must manually reset the brake cam inside the cover until the band expands to fit over the clutch drum. Additionally, ensure the bar tensioner pin is perfectly aligned with the hole in the guide bar, as even a slight misalignment will prevent the cover from seating flush.
On a Honda TRX520 Foreman, a display that won't shut off is typically caused by a failed ignition switch or a stuck main relay that is keeping the 'switched' power circuit energized. To diagnose, unplug the 4-pin ignition switch connector; if the screen goes dark, the switch is internally shorted. If it stays on, you likely have a fused main relay or an aftermarket accessory backfeeding power into the harness.
Check for a glazed CVT belt or flat-spotted primary clutch rollers, which are the most common causes of jerking and metallic rattling on 2013 Arctic Cat models. Remove the CVT cover and inspect the belt for 'hour-glassing' and the one-way bearing for seizure, which forces the machine to creep or jump when shifted into gear. If the belt is fine, inspect the driveline U-joints for play that creates a rhythmic rattle under load.
If your Troy-Bilt Bronco cranks but won't start, first spray a two-second burst of starting fluid into the air intake; if it fires briefly, you have a fuel delivery issue, likely a stuck fuel solenoid or a clogged carburetor. If it doesn't fire at all, check for a spark using a tester to ensure the ignition coil isn't grounded by a safety switch. Most Broncos use the Briggs & Stratton Intek engine, which is prone to fuel solenoid failures and valve lash issues (needs 0.004" gap) that prevent starting.
A Briggs Intek engine blowing oil is usually caused by an overfilled crankcase, a blocked breather tube, or worn internal piston rings. Start by checking your oil level and ensuring your air filter isn't soaked with oil before attempting more complex repairs.
First, verify the oil level is at the very edge of the fill neck; the Oil Alert system will ground the ignition if it is even slightly low. Ensure the fuel cap vent is set to 'ON' and the main switch is in the 'RUN' position. If it pulls over but won't fire, the pilot jet inside the carburetor is likely clogged with stale fuel varnish, which is the most common failure on the GXR120 engine.
To diagnose a Stihl MS 250 that cranks but won't fire, first confirm ignition by performing a spark test using an NGK BPMR7A plug. If spark is present, inspect the spark arrestor screen in the muffler for carbon blockage, a very common Stihl failure that prevents the engine from breathing. If the saw still won't fire, verify fuel delivery by checking for hardened carburetor diaphragms or a disconnected impulse line located behind the carburetor.
On the Kohler Command 20hp (CH20/CV20), the most common culprit for a crank-no-start is a stuck fuel shut-off solenoid at the base of the carburetor. Verify that the solenoid clicks when the ignition is turned to 'ON' and ensure you have 12V DC at the red/white wire. If the solenoid is working, check for spark on both cylinders using a gap tester set to 0.030 inches, as these engines utilize dual independent ignition modules that can fail individually.
An ATV battery that keeps dying is usually caused by either an old battery that can no longer hold a charge or a faulty charging system component like the stator or voltage regulator. Start by testing the battery voltage and inspecting the connections for corrosion, then move on to checking if the charging system is working while the engine is running.
If your 2017 Yamaha has 'not enough power to crank,' the most likely culprit is a sulfated battery or a failing starter relay. First, perform a load test with a multimeter; voltage should not drop below 10.5V while pressing the start button. If the battery holds voltage but the engine won't turn, bridge the two large terminals on the starter solenoid with a heavy-gauge screwdriver to see if the starter spins—if it does, the solenoid or its trigger circuit is faulty.
If your Troy-Bilt 13WX78BS011 (typically powered by a Briggs & Stratton 17.5 HP Intek) fires briefly then dies, the most likely culprit is a sticking fuel shut-off solenoid at the base of the carburetor or a clogged main jet. The engine is successfully igniting the initial 'prime' of fuel but failing to maintain a flow from the carburetor bowl into the combustion chamber. Check for 12V at the solenoid wire and ensure the carburetor's internal plastic emulsion tube isn't obstructed by varnish.
The most common reasons a Predator 212 engine won't start are stale fuel or a dirty carburetor. Start by checking your fuel level, verifying the ignition switch is on, and ensuring the fuel valve is open.
Engine surging, or 'hunting' for speed, is almost always caused by a restricted fuel flow or a vacuum leak preventing the engine from maintaining a steady RPM. Start by cleaning the carburetor and replacing stale fuel before moving on to checking air intake components.
Most Briggs and Stratton engines fail to start due to old fuel clogging the carburetor or a fouled spark plug. Start by checking your fuel quality, ensuring the fuel shut-off valve is open, and verifying that the spark plug wire is firmly connected.
The most common reason a Generac GP3500iO won't start is the low oil shutdown sensor being triggered by a low oil level or the unit not being on a level surface. Check that the oil is at the very top of the fill threads and that the fuel dial is fully in the 'ON' position. If it still won't fire, spray a 2-second burst of carburetor cleaner into the air intake; if it starts briefly, your carburetor's main jet is clogged and needs cleaning.
On the Arctic Cat Alterra 700, the most common 'cranks but won't start' culprit is low battery voltage during cranking; if the voltage drops below 10.5V, the EFI ECU will not trigger the fuel injector even if the starter sounds healthy. First, listen for the 2-second fuel pump prime when the key is turned to 'ON' and verify the kill switch is not in the 'OFF' position. If you have no prime, check the EFI relay and the fuel pump fuse in the main fuse block.
First, verify the oil level is at the very top of the fill threads; the WGen7500's low-oil sensor is highly sensitive and will cut spark even if it's slightly low. If oil is good, perform a 'shot test' by spraying carburetor cleaner into the air intake; if it fires briefly, you have a fuel delivery issue, likely a clogged main jet or a stuck fuel solenoid at the bottom of the carb. For electric start models, ensure the battery is showing at least 12.4V, as a weak battery can spin the engine but fail to provide sufficient voltage for the ignition module.
A squealing or slipping UTV belt is usually caused by a worn belt, moisture inside the clutch housing, or dirty sheaves. Start by inspecting the belt for glazing or cracks and cleaning the clutch faces to ensure a proper grip.
If your Honda Foreman 520 is stuck in 4WD, it may be due to a faulty actuator, a stuck lever, or an electrical issue. Begin by checking the actuator and ensuring the lever is not jammed or damaged.
On a Yamaha Grizzly 700, a no-crank condition is usually tied to a low battery (under 12.6V), a corroded frame ground, or a failed brake safety switch—if the brake light doesn't illuminate when the lever is squeezed, the starter circuit is locked out. Begin by verifying the 30A main fuse near the battery and jumping the starter relay terminals to see if the starter motor rotates. If jumping the relay works but the button does not, the issue lies in the handlebar switch, brake interlock, or neutral safety circuit.
For a Troy-Bilt 13WX78BS011 that won't crank, first verify the battery has at least 12.4V and the 20-amp fuse behind the dash is intact. Most no-crank issues on this Pony model stem from a faulty brake safety switch under the left frame or the PTO (blade) lever not being fully disengaged. If you hear a click but no rotation, jump the solenoid terminals to isolate whether the solenoid or the starter motor has failed.
If your Bad Boy Maverick HD won't start, it may be due to issues with the battery or fuel system. Begin by checking the battery voltage, connections, and ensuring there's fresh fuel in the tank.
Most-needed maintenance items to keep your equipment running.
The cheapest, fastest fix for most small engine starting problems.
Find on AmazonCleaning the carb is the #1 fix for surging and stalling engines.
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