It would probably be worth your wild to learn to tune it up on your own...(?) Well, if you are trying to save on expenses. Most shops charge around $70 an hour to look at a motor. A tune-up would probably run you around $150-200 with parts. You can do it for about $30-40 and have a better understanding of your motor in case you have issues on the water.
Check out this link.
It will give you a good idea on how to tune up your motor.
*I am pretty sure that motor will have some carberator gunk in one of the jets. Every motor gets them by sitting just a few months. It will cause your motor to idle rough and to not hit wide open throttle.
Start by taking the carb. off and soaking it in cleaner over night. Be sure and take all the needs out and see if you can see light through the holes. You will probably see a dark - gunk obstruction in the back of the holes. Be sure and blow those out really good. Put the bottom plate back on with the carb. upside down and make sure the float rests level.
Reseat all of your idle needles and be careful not to over tighten them and cause damage to the tips. [Put the idle screw back in the number of turns you counted taking it out. If you have forgotten how many turns, screw it in until it bottoms and then turn it out 1 3/4 to 2 turns. That will be close enough to get started.]
Be sure and get a small gas tank. I would never get more than a gallon of gas per trip and mix correctly. Gas will foul after a month of sitting and run horrible in your motor.
Here is one of the best links for information about motors and the boat parts are fairly priced.
Hope this helps...