What procedures are included in the Visible Smoke Test?

• A. Idle Test, Crankcase Test, BAR Snap Test.
• B. Idle Test, Crankcase Test.
• C. Crankcase Test, BAR Snap Test.
• D. Idle Test, BAR Snap Test.

Answer: (A)

The Visible Smoke Test checks for smoke emissions under different engine conditions to identify oil- or fuel-burning issues. It uses three procedures to cover common smoke scenarios: the Idle Test, the Crankcase Test, and the BAR Snap Test.

In the Idle Test, the engine runs at normal operating temperature and steady idle while you observe the exhaust for any visible smoke. This shows smoky conditions that appear at light, steady operation.

The Crankcase Test focuses on smoke sources related to the engine’s crankcase and oil system. It helps distinguish smoke coming from burning oil or crankcase-related issues from smoke produced by the fuel system.

The BAR Snap Test involves a rapid throttle snap to higher RPM to stress the engine and provoke emissions, revealing smoke that might not show up at idle. This is essential because some engines only show noticeable smoke during quick acceleration.

Together, these three procedures ensure you detect smoke that appears at idle, smoke tied to oil/crankcase issues, and smoke that only comes out during a quick engine load change. Leaving out any one of them could miss a smoky condition, which is why the full Visible Smoke Test includes all three.