25 HP Kohler Command Pro Engine Problems [with 4 easy fix]
The 25 HP Kohler Command Pro engine is widely used on mowers, blowers, and other equipment because of its robust performance and commercial-grade design. That said, like any mechanical system, it can develop issues over time, especially when maintenance slips or parts wear.
Below is a structured look at the most common problems owners face, how to spot them, and practical fixes you can try.
🔧 Common Problems with 25 HP Kohler Command Pro Engines
| Issue | Typical Cause | Main Symptoms |
|---|---|---|
| Engine surges | Dirty carburetor, contaminated fuel | Unstable RPM, power fluctuates |
| Hard starting | Weak spark, clogged fuel line | Engine cranks but won’t start |
| Overheating | Poor oil quality, vapor lock | Hot engine, burning smell |
| Loss of power | Blocked fuel or air filter | Poor performance under load |
| Smoke emissions | Dirty air filter, incorrect mix | Black or gray smoke |
| Spark problems | Faulty plugs or ignition module | Misfires or stalls |
Read: Kohler Courage 26 Hp Engine Problems [+ Fixes]
25 HP Kohler Command Pro Engine Specs
The 25 HP Kohler Command Pro is a standard option for various uses. Its range of compatibility covers heavy and light elements that require power. Let us have a look at the specs of this engine to get a better view:
- Fuel Type: Gasoline
- Displacement: 725 cc
- Bore: 83 mm
- Stroke: 73 mm
- Oil Capacity: 1.9 L
- Certified RPM: 3600
- Dry Weight: 43 Kg
- Engine Type: Commercial
- Compression Ratio: 9.0:1
🛠️ Troubleshooting & Fixes
1. Engine Surges & Unstable RPM
Causes:
- Contaminated or ethanol-damaged gasoline
- Dirty air intake or carburetor blockages
Symptoms:
- Ups and downs in engine speed
- Vibrations or rough running
Fix Steps:
- Clean/Replace Air Filter – A clogged filter chokes fuel/air balance.
- Inspect Carburetor – Remove and clean jets and float assembly.
- Check Fuel Quality – Drain old fuel; use fresh gas with stabilizer.
2. Engine Overheating
When the engine gets hotter than the optimum level, the engine’s dying possibilities are high. The prime reasons behind this problem are as follows:
- Oil-degraded motor oil
- Defected Solenoid Plug
- Carburetor vapor lock
- Defective Spark Plugs
You can get a prior idea about this problem before it gets serious through the following symptoms:
- Burning smell
- Coolant leaks
- Misfiring engine
- White smoke
READ: 27 HP Kohler Engine Problems Troubleshooting
How to fix?
You can try out multiple fixes for this problem. Let me take you through each of them in the sections below:
a) Change The Oil
Since one of the causes is improper oil quality, you should focus on changing that. Let’s have a look at the steps:
- Step 1: Check the oil color. Using the fuel tank dipstick, inspect the current oil color.
- Step 2: Replace Oil. If the oil color is brown, change the oil and, if necessary, replace the oil filters.
b) Replace Cooler
It is a solution when vapor lock is the reason behind the engine getting overheated. Follow the steps below to learn more:
- Step 1: Arrange Tools. Manage tools like screwdrivers, wrenches, and vice grips to start the process.
- Step 2: Pinch the fuel line. Use the vice grips to pinch the fuel line. It will aid you in turning off the gas in the carburetor.
- Step 3: Remove the Cooler. With the help of the screwdrivers, unhook the cooler and remove it.
- Step 4: Install New Cooler
3. Faulty Spark Plugs
The issue with the defective spark plugs is one of the critical problems with the Kohler engine. These spark plugs may become faulty due to damaged wiring, dirty spark plugs and worn out plugs.
Whenever these spark plugs become defective, the following symptoms will be noticeable:
- The engine stalls shortly after starting
- Increase in fuel consumption
- Engine runs rough
READ: Kohler EFI Engine Problems [Troubleshooting Guide]
How to fix?
The easiest way to fix this issue is to replace the spark plugs. Let me take you through the steps:
- Step 1: Cool down your engine. Before navigating to the spark plugs, cool down your 25 HP Kohler Command Pro.
- Step 2: Remove the Wire. After the engine has cooled down, you must remove the wire from each plug.
- Step 3: Use a socket. Remove the old spark plug with the help of a spark plug socket.
- Step 4: Install a new spark plug. Thread the new spark plug carefully into the cylinder head. Use the socket to tighten it firmly.
4. Bad Smoke Emission
Engines producing harmful smoke are a common issue, which also occurs in the case of Kohler engines. It might happen due to the following reasons:
- Dirty Air Filter
- Unadjusted Carburettor
- Defective Head Gasket
In this regard, the symptoms evident are listed as follows;
- Black smoke during acceleration
- Gray smoke during starting of the engine
How to fix?
Most of the time, the problem originates from a dirty air filter. You must replace it to fix this issue.
- Step 1: Remove the air filter cover – Start the process by rotating and taking out the air filter cover.
- Step 2: Remove the old air filter – After taking out the cover, remove the old air filter.
- Step 3: Position the new air filter on the cover – Install the new one by precisely positioning it.
- Step 4: Insert the cover into the housing – The process will end with the installation of the air filter cover from where you detached it. Rotate the knob firmly to make it secure.
For more detailed view please watch this video below about kohler lawn mower engine air filter replacement.
Are Kohler Command Engines Reliable?
Traditionally, Kohler has offered excellent engines that are highly reliable. These engines are popular choices for equipment like lawn mowers and tractors.
That said, Kohler command engines provide economical and efficient solutions for this equipment. The functionalities of these engines make them easy to operate, and most models can cater to your specific needs.
🧠 Maintenance Tips to Prevent Problems
Routine maintenance is the #1 way to keep a Kohler Command Pro running reliably:
- Change oil every 100 hours (or earlier in dusty conditions).
- Replace spark plugs and fuel filters at recommended intervals.
- Keep the carburetor and air intake clean.
- Use fresh, ethanol-free fuel when possible.
❓ FAQs — 25 HP Kohler Command Pro Engine
Q: How long should a Kohler Command Pro engine last?
With good maintenance, many users report 7,000–9,000 hours of reliable operation.
Q: Why does the engine lose power under load?
Loss of power can stem from blocked air or fuel filters, poor carburetor adjustment, or governor linkage issues.
Q: How often should I change the oil?
Best practice is to change oil every 100 hours or annually, whichever comes first.
Q: What kind of smoke is normal?
A small amount of gray smoke during cold start can be normal, but persistent black smoke usually indicates rich fuel mixture or airflow issues.
