What is the recommended dose of amoxicillin for an adult with an ear infection?

You should take a child to the doctor if you suspect they have any kind of infection - different antibiotics treat different types of infections and what you believe to be an ear infection could be an entirely different infection that may be causing their ear to hurt - then you would be giving the child amoxicillin unnecessarily which could cause him to develop an immunity to that antibiotic and he will need a stronger antibiotic in the future for an infection that could have been treated with amoxicillin. And if he does have an ear infection for real, the doctor will know exactly what dose and strength is needed since there are also many different strengths of that antibiotic.