2007 Johnson 2 HP 4-Stroke Service Manual, Page 123Get this manual
GEARCASE LEAK TEST
Inspection
Inspect the lubricant for water contaminationWater in the lubricant can cause milky appearance, however normal aeration can also cause the same appearanceTo check for water contamination, drain lubricant into suitable glass containerAllow the drained oil to settle for minimum of one hour to determine if there is an abnormal amount of water in the oilSome gearcase lubricants are designed to mix with small amount of water from normal water vapor condensation within the gearcaseRefer to LEAK TEST on p123Overheated lubricant will give the lubricant black color and burned odorInternal gearcase inspection is recommended when lubricant is contaminated or shows signs of failure
LEAK TEST
Check for leakage of the oil seals and O-ring when applying the specified pressure inside of the gearcaseInstall leakage tester into the oil level holeConnect an air pump to leakage testerRotate the driveshaft and the propeller shaft clockwise several times and then apply the specified pressure for the test