What is the purpose of a cold cylinder check?

What is the purpose of a cold cylinder check?

• A. A cold cylinder check determines which cylinder is not firing. Run the engine for a few minutes at the speed, and on the magneto, at which it runs roughest. Shut it down and feel the exhaust stack near the cylinder head. The cylinder with the stack that is not as hot as the others is the cylinder that has not been firing.
• B. To check oil pressure.
• C. To measure fuel consumption.
• D. To test carburetor heat.

Answer: (A)

The main idea is to locate a cylinder that isn’t firing by comparing the heat of each exhaust stack. When an engine runs and one cylinder isn’t contributing combustion, that cylinder’s exhaust is cooler than the others. By running the engine at the speed where roughness is observed on the magneto that corresponds to the suspected misfire, then shutting down and feeling the exhaust stacks near each cylinder, the cooler stack points to the cylinder not firing. This directs you to inspect the spark, timing, valve clearance, or fuel delivery for that specific cylinder. It isn’t about oil pressure, fuel consumption, or testing carburetor heat, which don’t help identify a dead or nonfiring cylinder.

The main idea is to locate a cylinder that isn’t firing by comparing the heat of each exhaust stack. When an engine runs and one cylinder isn’t contributing combustion, that cylinder’s exhaust is cooler than the others. By running the engine at the speed where roughness is observed on the magneto that corresponds to the suspected misfire, then shutting down and feeling the exhaust stacks near each cylinder, the cooler stack points to the cylinder not firing. This directs you to inspect the spark, timing, valve clearance, or fuel delivery for that specific cylinder. It isn’t about oil pressure, fuel consumption, or testing carburetor heat, which don’t help identify a dead or nonfiring cylinder.