How is hydraulic lock removed?

How is hydraulic lock removed?

• A. Remove the spark plug from the locked cylinder, drain the oil, clean the spark plug, and replace it.
• B. Crank the engine vigorously until the oil drains.
• C. Replace the piston rings.
• D. Add oil to the cylinder.

Answer: (A)

Hydraulic lock happens when a liquid in the cylinder makes the piston unable to compress air, effectively locking the engine. The way to relieve it is to give the liquid a path to escape so the piston can move again. Removing the spark plug creates an opening, and turning the engine slowly lets the liquid be pushed out through the spark plug hole. Draining the oil helps ensure any liquid that’s infiltrated the crankcase or mixed with lubrication isn’t circulated back into the cylinder, and inspecting or cleaning the spark plug prevents fouling when you restart. Once the cylinder is dry, reinstall the plug and resume normal operation.

Hydraulic lock happens when a liquid in the cylinder makes the piston unable to compress air, effectively locking the engine. The way to relieve it is to give the liquid a path to escape so the piston can move again. Removing the spark plug creates an opening, and turning the engine slowly lets the liquid be pushed out through the spark plug hole. Draining the oil helps ensure any liquid that’s infiltrated the crankcase or mixed with lubrication isn’t circulated back into the cylinder, and inspecting or cleaning the spark plug prevents fouling when you restart. Once the cylinder is dry, reinstall the plug and resume normal operation.