Check the spark plugs for dirt and corrosion if the engine will not start. Wipe the plugs clean or replace them if necessary.
Check the gas tank for sufficient fuel. Go over all of the fuel lines and connectors for any damage or wear and tear. Replace fuel lines as necessary. Test the rubber primer bulb for resistance. If fuel is not reaching the engine, have the fuel-line assembly replaced.
Remove the plastic cover to the motor and check for any oily residue. If you notice oil, this could mean that the rings are wearing out. Have a qualified marine mechanic check this out for you.
Inspect the engine seals (gaskets) for wear and tear. If the seals are damaged this could lead to a loss of vacuum in the system. Check for any cracks in the engine cowling.
Attach the air conditioner compression gauge to the system to check the pressure in the motor. If the reading is not between 90 PSI (Pounds Per Square Inch) and 60 PSI, have a qualified marine mechanic service your outboard engine.
If the engine is still unable to turn over, even after using the primer bulb, try pouring a small amount of fuel directly into the carburetor while pulling the starter cord at the same time.
