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Four Stroke Compression Leak down Test
Tool : Four Stroke Leak Down TesterEngines are compressors, compression testing is the best troubleshooting and general diagnostic tool available for quick condition check. Remove the spark plug wire and plug Inspect the plug for color and deposits , light tan is good Set piston TDC Thread tool into the plug hole Pressurize 6 to 8 PSI Air escaping from the carburetor = intake valve problems Air escaping from the exhaust = exhaust valve problems Air escaping from the crankcase = ring problems Bubbling sounds at the head gasket = blown head gasket STANDARD COMPRESSION TEST
Tool: Compression TesterTurn ignition off Remove spark plug Thread tool into the spark plug hole Set throttle wide open Turn engine over five or six times Check reading several times ( Reset tool to zero after each test) If compression is less than 100PSI perform leakdown test No Compression Tester?
Place your thumb over the spark plug hole ( press down hard )Turn the engine over If air is not escaping around your thumb you have low or no compression Simple troubleshoot low compression engine Put one tsp. of oil in the cylinder through the spark plug hole. Run compression test Higher compression = ring problem No compression change = valve problem ( try checking valve tappet clearance then retest) |