How to Troubleshoot a 75 HP Marine Boat Motor

Many people grew up watching television shows such as "Gilligan's Island" and wondering how they would survive if they were ever marooned because of a broken down boat. If you take the time to learn a few basic tips, you can avoid dealing with this situation. A 75 HP marine motor is similar to other small outboard marine motors in regard to how it is built. If you can learn to troubleshoot a motor this size, you will be able to troubleshoot other sizes as well.

Instructions

    • 1

      Inspect the fuel system of your 75 HP marine boat motor and ensure that there is enough fuel in the tank. Inspect any fuel lines for leaks and locate the primer bulb connected to the main fuel line. Test the bulb to see if it is hard or if it cracks under pressure. If either of these factors exist, have the bulb replaced or replace it yourself.

    • 2

      Remove and clean the spark plug. Corrosion can stop the spark plug from producing a spark. Clean the spark well to remove and dirt or corrosion. Replace the plug if it is broken or appears to be burned.

    • 3

      Inspect for oil splatter or leaks by removing the plastic cowling on the motor. If oil splatter exists, you could have an issue with your piston rings failing because of excessive wear. Contact a mechanic to inspect the motor if oil splatter is an issue.

    • 4

      Locate and inspect the rubber gaskets that are in between engine parts. Inspect these gaskets for wear, hardness and breakage. Replace any worn gaskets to ensure proper vacuum pressure when the engine is running.

    • 5

      Remove the engine's spark plug and connect a compression test gauge. Look for an ideal reading between 60 and 90 lbs. per square inch. Contact a mechanic if you see a lower reading.