There are quite a lot of little tasks to do when you are going to service your outboard engine.
If you use this checklist you should cover just about everything:
1.  Change the gear oil – and while you are doing this see if any water
     has got through the seals.
2.  Replace the spark plugs – some people just clean the old ones, but
     buy new.
3.  Strip down and clean the fuel filter.
4.  Strip down the water pump – clean any corrosion.
5.  Check the flywheel nut and nuts around the cylinder head.
6.  Check the recoil starter – lubricate it – also the pull rope for any
     wear.
7.  Check the gear and throttle cables for any damage – lubricate all
     linkages.
8.  Check the tilt mechanism – grease it and the clamp screws while
     you have the grease out.
9.  Lubricate the prop shaft.
10. Bleed the auto lube pump – check for air in system.
11. Check the ignition timing – adjust if needed.
12. Adjust the carburettor pilot screws if they need it – otherwise
      leave as is.
13. Change the engine oil.
 
Start your outboard up after doing these tasks and listen to it. Check to see if water is exiting the exhaust. Then adjust the throttle – the engine should have a smooth pick from idle. The maximum revs should be achieved. Return to idle speed and check to see if does maintain its correct idle speed , now that the engine is hot. With the throttle
working smoothly, check all other functions, including the stop button!  Happy motoring!