Kohler Engine Troubleshooting Guide

Kohler Engine Troubleshooting Guide

Have you ever had your lawn mower throwing a fit? If you own a machine with a Kohler engine, be it a lawnmower, tractor or generator, these engines are generally reliable.

But like all engines, they have their off days. So, what do you do when your Kohler engine starts acting up?

This Kohler engine troubleshooting guide is designed to help you solve common issues with Kohler engines.

We’ll break down the 11 typical issues you might face, from ‘won’t crank’ scenarios to overheating woes.

To get your engine running smoothly, you’ll need to look at some main factors like oil, fuel, air, and spark. We will show you how to check, fix, and return to mowing.

Ready to become an amateur mechanic for the day? Let’s roll up those sleeves and get started.

11 Common Kohler Engine Problems

  1.     Kohler engine won’t crank
  2.     Engine Overheats
  3.     Engine Knocks or Pings
  4.     Smoke Emission
  5.     Engine Vibrates Excessively
  6.     Kohler engine runs rough when hot
  7.     Kohler engine won’t start
  8.     Kohler engine won’t throttle up; Backfires
  9.     Stops Suddenly
  10.     Leaks from the Carburetor
  11.     High Fuel Consumption

Pre-Troubleshooting Process

Basic safety guidelines

Before you fix that Kohler engine issue, keep safety first. These engines are intricate machines that can be dangerous if not approached with caution.

Ensure you follow these basic safety guidelines to cut the risks:

  • Disconnect power source: Ensure the engine is turned off and unplug any electrical components.
  • Wear protective gear: Safety goggles, gloves, and a long-sleeved shirt can protect you from unexpected hazards.
  • Work in a well-ventilated area: Adequate airflow helps dissipate fumes and other harmful gases.
  • Avoid contact with hot or moving parts: Wait for the engine to cool down before you start your inspection.
  • Follow the manufacturer’s instructions: Refer to the manual by the engine manufacturer for safety and troubleshooting tips. You can refer to any other official guides as well.
Kohler Engine Troubleshooting Guide

Tools you will need

  • Screwdriver: For removing screws and panels.
  • Wrench: Essential for loosening and tightening various nuts and bolts.
  • Spark plug tester: To check the condition of your spark plugs.
  • Compression tester: Useful for diagnosing engine problems related to pressure.
  • Multimeter: A must-have for electrical diagnostics.

Troubleshooting Common Kohler Engine Problems

1. Kohler engine won’t crank

Starting failures are a common 17 hp Kohler engine problem. You may notice immediate symptoms when your Kohler engine won’t crank.

You push the start button; no sound or movement can be frustrating and confusing. This problem can stem from a variety of reasons.

Common Causes

  • Low Battery: It is the most common culprit. With enough juice, your engine will turn over.
  • Faulty Starter: The starter motor or solenoid could be the issue if your battery is fine.
  • Bad Ignition Switch: Sometimes, the problem lies in the ignition switch or the connecting wiring.

Troubleshooting Steps

  • Check battery voltage and connections: Use a multimeter to test if your battery has enough voltage. Also, ensure all battery connections are secure and free of corrosion.
  • Inspect starter motor and solenoid: If the battery’s good, the next step is to check the starter. Listen for a clicking noise when starting the engine that signals a faulty starter.
  • Test ignition switch and wiring: A bad ignition switch can prevent current flow. Use a test light or multimeter to confirm its status.
  • Replace or repair any defective parts: Sometimes, the only option is to replace faulty parts. Always refer to your owner’s manual for specifics on part replacements.

2. Engine overheats

Engine overheating is frequent, particularly with 25 hp Kohler Command Pro engine problems.

Symptoms of overheating include engine shutdown, visible smoke, and coolant leaks. These are clear indicators that your engine is running hotter than it should be.

Common Causes

  • Low Coolant Level: Inadequate coolant can’t dissipate heat well.
  • Dirty Air Filter: A clogged air filter limits airflow, affecting the cooling system.
  • Clogged Radiator: Reduced coolant flow can result from a blocked radiator, causing overheating.

Troubleshooting Steps

  • Inspect Cooling Fan and Thermostat: Ensure the cooling fan is operational, and the thermostat opens as it should.
  • Clean Air Filter and Radiator Fins: Remove and clean the air filter; clean any debris from the radiator fins.
  • Check Coolant Level and Quality: Top off the coolant if levels are low, and consider replacing it if the quality is poor.
  • Replace or Repair Defective Parts: Repair or replace the damaged components after diagnosing the issue.

3. Engine knocks or pings

Engine knocking or pinging is a common Kohler 5400 series engine problem.

You’ll often hear loud or irregular noises from the engine, especially when accelerating or the engine is under load. This noise is neither normal nor good for your engine’s long-term health.

Common Causes

  • Low-Octane Fuel: Fuel with a low octane rating is the culprit behind engine knocking.
  • Incorrect Timing: If the engine’s timing is off, it can result in knocking or pinging.
  • Faulty Spark Plug: A spark plug that’s seen better days can also contribute to this issue.

Troubleshooting Steps

  • Use Higher Octane Fuel or Add Fuel Stabilizer: Upgrading your fuel solves the problem. If that’s not possible, a fuel stabilizer might do the trick.
  • Check Timing and Adjust if Necessary: Consult your engine’s manual on how to check and adjust the timing.
  • Inspect Spark Plug and Replace if Worn or Fouled: A simple spark plug replacement can sometimes make all the difference.
Kohler Engine Troubleshooting Guide

4. Smoke emission

Smoke emission is frequently reported in Cub Cadet Kohler engine problems.

Smoke emitting from the exhaust is a tell-tale sign that something’s not right and is often color-coded.

You may observe black, blue, or white smoke coming out. Each color indicates a different problem.

Common Causes

  • Black Smoke: Generally caused by a rich fuel mixture.
  • Blue Smoke: Usually the result of leaking oil into the combustion chamber.
  • White Smoke: It indicates coolant is getting into the combustion chamber.

Troubleshooting Steps

For Black Smoke:

  • Adjust Carburetor Settings or Replace Faulty Parts: Too much fuel and not enough air can cause black smoke, so check your carburetor settings.
  • Clean or Replace Air Filter: A dirty air filter can exacerbate the issue.
  • Check Fuel Pump Pressure and Regulator: Too much fuel pressure could be the cause, so it’s worth checking.

For Blue Smoke:

  • Check Oil Level and Quality: Too much oil leaks into the combustion chamber.
  • Inspect Valve Seals and Piston Rings for Wear or Damage: A worn seal or ring can let oil flow into places it shouldn’t be.
  • Replace Head Gasket if Blown: This is often a worst-case scenario but could be the culprit.

For White Smoke:

  • Check Coolant Level and Quality: Low or poor-quality coolant can lead to white smoke.
  • Inspect Cylinder Head and Block for Cracks or Warping: Coolant leakage could occur through cracks or warps.
  • Replace Head Gasket if Blown: Like with blue smoke, this is a worst-case scenario but a possible one.

5. Engine vibrates excessively

Engine vibration issues are commonly reported in 20 hp Kohler Command engine problems.

If your Kohler engine starts acting like part of a heavy metal concert, you’re dealing with excessive vibration.

Symptoms include pronounced shaking, noise, and a noticeable drop in engine power.

Common Causes

  • Loose or Broken Parts: Sometimes, it’s as simple as a loose bolt; other times, something’s broken.
  • Unbalanced Flywheel: The flywheel helps regulate the engine. When it’s off-balance, you’ll feel it.
  • Bent Crankshaft: If your crankshaft is bent, it will cause vibrations and could lead to more severe engine problems.

Troubleshooting Steps

  • Check Mounting Bolts and Tighten if Loose: A loose bolt can cause more problems than you might think. Tightening it could solve your issue.
  • Inspect Flywheel and Balance if Needed: Use a flywheel balancer to balance the flywheel. Correct as necessary.
  • Examine Crankshaft and Replace if Bent or Damaged: A bent crankshaft is bad news and usually needs replacing.

6. Kohler engine runs rough when hot.

Rough-running engines, when hot, are frequent among Kohler 5400 series engine problems.

When your Kohler engine starts to feel more like a rebellious teenager than a well-behaved machine, you might notice it running rough once it gets hot.

Signs include stalling, hesitations, and misfires, especially when the engine is under load.

Common Causes

  • Dirty Carburetor: Over time, gunk and debris can accumulate in the carburetor.
  • Faulty Ignition System: Weak or inconsistent ignition can cause an uneven idle or misfire.
  • Low Compression: An engine needs adequate compression to run. Low compression can be a culprit here.

Troubleshooting Steps

  • Clean Carburetor Jets and Passages: Use a carb cleaner to remove any gunk or debris. Sometimes, a clean carburetor is all it takes.
  • Test Spark Plug Wires and Coils: Use a multimeter to test the spark plug wires and coils. Replace any that are not functioning well.
  • Check Compression: Use a compression tester to measure the engine’s compression. It might be time for more extensive repairs if it’s too low.

7. Kohler engine won’t start.

Picture this: You turn the key or press the starter button, eagerly waiting for the engine to roar to life.

Instead, you get silence, or the engine cranks but doesn’t start. It’s a universal sign that something’s off.

Starting failures are common in 17 hp Kohler engine problems. Here are some causes:

Common Causes

  • Lack of Fuel: No fuel, no go. Simple as that.
  • Air Issues: An engine needs the right air-to-fuel ratio to ignite.
  • No Spark: Without a spark, the fuel-air mix can’t ignite.
  • Low Compression: Even with fuel, air, and a spark, low compression can still stop an engine from starting.

Troubleshooting Steps

  • Check Fuel Level and Quality: Ensure you have enough fuel and it’s not old or contaminated.
  • Inspect Fuel Filter and Lines: Look for clogs or leaks that could impede fuel flow.
  • Spark Plug Check: Clean or replace the spark plug and ensure the correct gap setting.
  • Test Ignition Module and Coil: Use a spark tester to confirm they’re working properly.
  1. Compression Test: Use a compression tester to ensure the engine has enough compression to start.

8. Kohler engine won’t throttle up

Throttling and backfiring issues are common in Kohler 24-hp engine problems.

You hit the throttle, expecting a smooth increase in speed and power. But your Kohler engine either doesn’t respond, or its speed surges up and down. It’s as frustrating as a buffering video stream when you’re at the good part.

Common Causes

  • Dirty or Misadjusted Carburetor: Like a musician out of tune, a dirty carburetor can throw your whole engine off-key.
  • Vacuum Leaks: A vacuum leak can be the silent killer of engine performance.
  • Governor Malfunction: If the governor is acting up, you can forget about stable engine speed.

Troubleshooting Steps

  • Adjust Idle and Main Jets: Consult your manual for the correct settings.
  • Check Intake Manifold and Gaskets: A can of carb cleaner can help you find leaks. Spray it around the manifold and gaskets while the engine is running. Any change in idle indicates a leak.
  • Inspect Linkage and Springs: Look for signs of wear or damage and replace if needed.

9. Stops suddenly

Kohler Courage engines are particularly prone to stopping suddenly while running or not restarting after stopping.

It can cause severe disruptions in your tasks. It is a most common Kohler courage engine problem.

Common Causes

  • Low Oil Pressure: The engine’s safety mechanism might trigger, shutting it down to prevent damage from low oil pressure.
  • Overheating: Excess heat can engage the engine’s thermal safety features, leading it to shut down to prevent further damage.
  • Electrical Failure: Faulty or disconnected wires can interrupt the power supply, causing an unexpected engine shutdown.

Troubleshooting Steps

  • Low Oil Pressure: Check and fill oil to the recommended levels. Ensure you use the oil grade specified in the user manual or the oil and gas industry.
  • Overheating: Make sure the coolant is at the proper level and quality. Inspect the cooling fan and thermostat for proper operation.
  • Electrical Failure: Check wiring connections and fuses. Use a multimeter to test the ignition and safety switches for proper functionality.

10. Leaks from the carburetor

Engines from the 25 hp Kohler Command Pro series often experience carburetor leaks. It is noticeable as fuel dripping or spraying when the engine runs off.

Common Causes

  • Dirty or Worn Needle Valve, Float, or Gasket: Accumulated debris or wear can cause these components to fail, leading to leaks from the carburetor.
  • Faulty Fuel Pump: A malfunctioning Kohler fuel pump can cause excessive pressure, forcing fuel out of the carburetor.

Troubleshooting Steps

  • Dirty or Worn Needle Valve, Float, or Gasket: Clean or replace the needle valve, float, and gasket to prevent further leaks.
  • Faulty Fuel Pump: Check fuel pump pressure and regulator. If they are out of specification, replace or repair them as needed.
  • Additional Steps: Inspect and replace the fuel line if it is cracked or damaged.

11.  High fuel consumption

High fuel consumption is common in Kohler 5400 Series engines, where fuel combustion is higher than normal.

Common Causes

  • Rich Fuel Mixture: If the engine gets more fuel than it needs, it will burn through the supply quickly, leading to high consumption.
  • Leaky Fuel System: Leaks in the fuel tank, lines, or carburetor can cause a rapid loss of fuel.
  • Faulty Oxygen Sensor: A malfunctioning oxygen sensor can provide incorrect data, causing the engine to use more fuel.

Troubleshooting Steps

  • Rich Fuel Mixture: Lean the fuel mixture by adjusting carburetor settings or replacing faulty parts.
  • Leaky Fuel System: Inspect the fuel delivery tank, filter, lines, and carburetor for leaks and repair them as needed.
  • Faulty Oxygen Sensor: Test the oxygen sensor with a multimeter and replace it if faulty.

Advanced Troubleshooting Techniques

Using diagnostic tools

Diagnostic tools are electronic devices and software that identify and solve engine issues. They help in troubleshooting Kohler engines by providing real-time data and diagnostic codes.

Types of Diagnostic Tools

  • Scan Tools: Devices that read and interpret the engine’s data in real time.
  • Code Readers: Tools to pull error codes from the engine’s computer.
  • Oscilloscopes graph electrical signals, allowing you to observe the engine’s electrical patterns in real time.
  • Multimeters: They measure electrical values like voltage, resistance, and current.

Here is how to use them

Reading Error Codes:

  • Connect the scan tool or code reader to the engine’s diagnostic port.
  • Turn on the engine or set it to accessory mode.
  • Read the error code displayed on the tool’s screen.

Monitoring Engine Parameters:

  • Use a scan tool that can interpret live data.
  • Check real-time data such as temperature, RPM, fuel mixture, etc.

Testing Components:

  • Use a multimeter to test electrical continuity, voltage, and resistance on components like sensors and switches.
  • An oscilloscope can observe how well components like the ignition coil work in real time.

Understanding the Basic Components of a Kohler Engine

The fuel system

The fuel system is crucial for storing and delivering the fuel your Kohler engine needs. It comprises several key parts, such as the fuel tank, fuel pump, and carburetor or fuel injectors. Fuel filters are also in place to ensure the fuel is clean before entering the engine. 

The ignition system

The ignition system ignites the fuel-air mixture in the engine’s cylinders. It includes the battery, ignition coil, and spark plugs. When you turn the key, the system uses electrical energy from the battery to generate a spark, which is required to ignite the fuel.

The cooling system

The cooling system’s role is to regulate the engine temperature and prevent overheating. It consists of the cooling fan, thermostat, and radiator, which work together using coolant. This fluid cycles through the engine, absorbing and dissipating heat to ensure optimal performance.

The lubrication system

The lubrication system reduces friction between the engine’s moving parts. It consists of an oil pump, oil filter, and oil pan.

The pump circulates oil from the pan to the engine’s various components, and the filter removes any contaminants to keep the oil clean.

kohler engine troubleshootigg

Consulting the Service Manual

When you’ve got a problem with your Kohler engine, the service manual is your best friend. It tells you how to fix issues and keep the engine in good shape. It’s got pictures, tables, and step-by-step guides.

Look closely at the pictures and tables. They often have small details that are of help. Ensure you read everything so you get all the helpful info.

You can even download the Kohler engine manual online to have it with you all the time on your phone or tablet.

It’s a must-have tool for anyone owning a Kohler engine. Always check the latest version for the most current info.

Table: Common Problems and Causes in Kohler Engines

Common ProblemsLow BatteryDirty Air FilterWorn Spark PlugTiming IssuesFuel IssuesMechanical system FailuresElectrical IssuesLow Oil
The engine won’t crank
Engine overheats
Engine Knocks or Pings
Smoke Emission
Engine Vibrates Excessively
Runs rough when it is hot
The engine won’t start.
The engine won’t throttle up.
Engine backfires
Engine stops suddenly
Leaks from the Carburetor
High Fuel Consumption

Kohler Engine Maintenance Tips for Longevity

  1. Change Oil and Clean Filter: Change the oil to keep the engine happy. A clean filter helps the engine breathe easier. Both are good for your engine.
  2. Look at Spark Plugs and Fuel Lines: Check your spark plugs and ensure your fuel lines are okay to help the engine start safely.
  3. Keep It Cool and Check Battery: Ensure the engine stays cool and your battery is good. A cool engine and a good battery mean fewer problems.
  4. Check Belts and Do Check-Ups: Look at the belts to ensure they’re okay, and check the engine now and then. Finding problems can save you a lot of trouble later.
  5. Use Good Oil and Fuel: Use the right oil and fuel to help the engine work smoothly and last longer.
  6. Read the Manual: The manual tells you everything you need to know about your engine. Reading it can help you fix problems before they get worse.


Is it safe to troubleshoot a Kohler engine by myself?

Yes. It is generally safe to troubleshoot a Kohler engine by yourself. Always follow safety guidelines and consult the service manual for accurate information. It’s advisable to seek professional help to ensure proper diagnosis and repair for more complex issues.

What are the most common issues encountered with Kohler engines?

The most common issues with Kohler engines include starting failures, engine overheating, knocking and excessive smoke emission. Other frequent problems are high fuel consumption and carburetor leaks. Regular maintenance can help prevent these issues. Always consult your service manual for specific troubleshooting steps.

What are the Kohler recalls?

Kohler recalled some engines because of safety worries. The engines in the recall are SH265, CH245, CH255, CH270, CH395, CH440, and ECH440. These engines are often in things like wood chippers, generators, and pressure washers. They were also sold by themselves. Always check for updates on recalls to stay safe.

What causes a Kohler engine to surge?

A Kohler engine might surge because of a blocked idle jet, meaning something is clogging the part of the engine that controls steady running when you’re not speeding up. Cleaning the idle jet can often fix the problem.

How do I know what Kohler motor I have?

To find out what Kohler motor you have, look for a silver decal on the side of the engine cover. This sticker will have the model number, serial number, and other details about your engine. Knowing these numbers helps when you need parts or services.


Troubleshooting your Kohler engine can seem tough, but it doesn’t have to be. Knowing common issues and their fixes can save you both time and money.

Always use the service manual for detailed guidance. Using the right tools for the job is also important.

Regular maintenance checks can keep your engine running for a long time. But it’s always best to ask for professional help if you need clarification. Remember, it’s better to be safe than sorry.