Which procedure is recommended for checking compression?

When checking compression in an engine, one of the methods involves bouncing the flywheel backwards against the compression stroke. This technique allows the technician to feel the resistance created by the cylinder's pressure when the piston reaches the topmost position during its compression stroke. If the engine has good compression, the resistance will be substantial, indicating that the compression is within a normal range. If the flywheel does not resist as expected, it suggests that there may be issues such as worn rings or valves that could be affecting the engine's ability to maintain proper compression.

The other methods presented, while they relate to engine diagnostics, do not directly assess the compression in the same effective manner as bouncing the flywheel. Checking the compression gauge does not provide an immediate tactile feedback about the compression's strength, and evaluating backpressure primarily addresses exhaust flow rather than compression itself. These factors can be useful for troubleshooting, but they do not serve as a primary method for checking compression as the correct choice does.