My father has always claimed that his backup outboard motor has a mind of its own. He claims this because the motor seems bent on not working properly at the exact times that my father needs it. Whenever he is about to take his boat out for the day, he tests the motor to see if it is going to work. When he does the test, the little motor always runs like a champ.
When he actually needs it later, it is a pain to start. My father says that the motor rebels based on the quality of two cycle outboard oil that he uses. When he uses high quality oil, it runs perfectly. When he uses a cheaper generic, the outboard motor refuses to start. The two might not actually be correlated, but my father is willing to appease the motor if it means getting it to start more easily.