Abstract: Oil venting and monitoring apparatus for marine outdrives. The apparatus includes an oil monitoring reservoir suitable for locating inside the boat. The reservoir is in fluid communication with the fully oil flooded head of the marine outdrive. The reservoir can be observed for an indication of oil level and oil condition. A clear plastic oil reservoir may be used to enhance visual observation. Unlike conventional outdrives, the oil reservoir is convenient for the addition of oil as necessary during and after operation. The apparatus is preferably designed with at least a one inch (1") diameter oil fill hole and typically is of one (1) quart or more oil capacity, so that an entire quart of oil can be quickly added to the system at one time. Also, audible and visual warning systems are included to warn the operator of a low oil condition, or of excess metal in the oil.