Valve clearance is the small gap between the valve and the rocker arm or camshaft in an engine. For Kohler engines, keeping this gap within spec ensures proper operation, prevents engine damage, and boosts longevity.
Kohler Valve Clearance Chart
| Engine Series | Model | Intake Valve (in) | Exhaust Valve (in) | Notes |
|---|---|---|---|---|
| Command PRO | CH620-CH740 | 0.005 – 0.007 | 0.010 – 0.012 | OHV |
| Courage | SV470-SV620 | 0.005 – 0.007 | 0.010 – 0.012 | OHV |
| 7000 Series | KT715-KT745 | 0.005 – 0.007 | 0.010 – 0.012 | OHV |
| Magnum | M18-M20 | 0.008 | 0.018 | Solid lifters |
| K-Series | K181-K582 | 0.008 | 0.018 | L-Head Design |
| Aegis | LH690-LH775 | 0.005 – 0.007 | 0.010 – 0.012 | Liquid Cooled |
| Confidant | ZT710-ZT740 | 0.005 – 0.007 | 0.010 – 0.012 | Twin-Cylinder |
Kohler Engine Model Numbers
Kohler engines are grouped by series (e.g., Command PRO, Courage, Magnum). Each series has unique valve clearance specs depending on size, camshaft, and cylinder design.
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Why Valve Clearance Matters in Kohler Engines
A properly adjusted valve:
- Ensures efficient air/fuel mixture intake and exhaust
- Reduces wear on the valve train
- Maintains optimal compression
- Prevents engine knocking or loss of power
Failing to adjust valve clearance at the right intervals can lead to poor performance, hard starts, and even costly repairs.
Kohler Engine Valve Adjustment Basics
Tools You’ll Need
- Feeler gauge
- Torque wrench
- Screwdriver and wrench set
- Service manual for your model
When Should You Check Valve Clearance?
- After 100 hours of use (initial)
- Every 300 hours of operation
- If the engine exhibits hard starting or loss of power
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How to Adjust Valve Clearance on Kohler Engines
Step-by-Step Instructions
- Let the engine cool completely.
- Remove the valve cover.
- Set the piston to the Top Dead Center (TDC) on the compression stroke.
- Use a feeler gauge to measure the valve clearance.
- Adjust by loosening the lock nut and turning the rocker screw.
- Retighten and recheck clearance.
- Reassemble components.
Pro Tips for Safe Adjustment
- Adjust cold for the most accurate settings.
- Don’t overtighten valve covers.
- Use manufacturer torque specs.
- Work in a clean environment.
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Symptoms of Incorrect Valve Clearance
Common Issues and How to Spot Them
- Hard starting
- Backfiring
- Low power
- Increased fuel consumption
- Tapping or knocking noises
If you notice these signs, check your valve settings immediately.
Kohler Valve Clearance – Overhead Valve (OHV) Engines
OHV designs are more efficient and compact. Most OHV Kohler engines (Command, Courage, 7000 Series) share similar clearance:
- Intake: 0.005 – 0.007 in
- Exhaust: 0.010 – 0.012 in
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Kohler Valve Clearance – Command PRO Series
Common in commercial mowers and utility equipment. Ensure exact clearance for:
- CH620-CH740
- CH750+
- EFI models may differ
Kohler Valve Clearance – Courage & 7000 Series
Often found in residential mowers. These engines require:
- Tight valve specs
- Regular maintenance due to lighter-duty design
Kohler Valve Clearance – Magnum and K-Series
These older engines use flatheads or side valves:
- Magnum M18-M20: 0.008 in (intake), 0.018 in (exhaust)
- K-Series: Similar specs; double-check with manual
Best Practices for Maintaining Kohler Engines
- Change oil every 50–100 hours
- Replace air filters regularly
- Use correct oil viscosity
- Perform annual tune-ups
- Check valve clearance every 300 hours
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FAQs
What is the valve clearance on a Kohler engine?
Valve clearance on Kohler engines typically varies by model. For most modern OHV Kohler engines (such as the Command PRO, Courage, and 7000 Series), the intake valve clearance is 0.005 to 0.007 inches, and the exhaust valve clearance is 0.010 to 0.012 inches.
Older models like the K-Series and Magnum have different specs, usually 0.008 (intake) and 0.018 (exhaust) inches.
What is the correct valve clearance?
The correct valve clearance depends on the engine model, type (OHV vs flathead), and its operational condition. Always refer to the Kohler service manual for your specific model. In general, a tight intake clearance (0.005–0.007 in) and slightly looser exhaust clearance (0.010–0.012 in) are standard for many Kohler engines.
What is normal piston to valve clearance?
Piston-to-valve clearance is the minimum distance between the piston and the valves during engine operation. While not typically user-adjustable or measured like valve lash, most Kohler engines are designed with safe piston-to-valve clearance of at least 0.080 inches (intake) and 0.100 inches (exhaust). This ensures valves do not contact the piston, even under thermal expansion.
What are the specifications for valve clearance?
Valve clearance specs vary by engine model. Here’s a quick breakdown of common Kohler specs:
- OHV Engines (Command PRO, Courage, 7000 Series):
- Intake: 0.005 – 0.007 in
- Exhaust: 0.010 – 0.012 in
- Flathead Engines (K-Series, Magnum):
- Intake: 0.008 in
- Exhaust: 0.018 in
Always confirm using your engine’s official service manual or consult the Kohler Engines Service Site.
What is the normal valve guide clearance?
Normal valve guide clearance for Kohler engines typically falls within:
- Intake Valve Guide Clearance: 0.0010 – 0.0030 inches
- Exhaust Valve Guide Clearance: 0.0015 – 0.0035 inches
Too much clearance can lead to oil consumption and valve instability, while too little may cause valve sticking.
How do you adjust a Kohler valve?
To adjust valve clearance on a Kohler engine:
- Let the engine cool completely.
- Remove the valve cover.
- Rotate the crankshaft until the piston is at Top Dead Center (TDC) on the compression stroke.
- Insert a feeler gauge between the rocker arm and valve stem.
- Loosen the lock nut and turn the adjustment screw until the gauge fits with a slight drag.
- Tighten the lock nut, recheck clearance, and reassemble.
What is the minimum valve clearance?
The minimum valve clearance ensures the valve can close completely as the engine heats up. For most Kohler OHV engines, the intake valve minimum is around 0.005 inches, and the exhaust minimum is around 0.010 inches. Going below this risks valve leakage and overheating.
What size is a Kohler valve?
Kohler valve sizes vary depending on the engine model and application. For example:
- Kohler Command PRO CH740 (OHV Twin):
- Intake Valve Head Diameter: Approx. 1.32 inches
- Exhaust Valve Head Diameter: Approx. 1.09 inches
Sizes can differ significantly by series. Always consult the parts manual or spec sheet for exact dimensions.
Final words
Maintaining the correct valve clearance on your Kohler engine is key to maximizing efficiency, performance, and engine life. Whether you’re tuning up a 7000 Series or rebuilding a Magnum, use this chart as your go-to reference. Don’t skip this vital maintenance step, your engine will thank you with years of reliable service.
