Part time job in Africa for a white guy?

What skills to you have that you think someone might be willing to pay for? Africa is a vast place, which country or countries are you going to?

Most big cities in Africa have a mixed population, though mostly 'black' of several shades.

Make sure you get all the legal bits in place for whichever country you want to study in and work in.   Visit government websites and get it all tied up - visas, work permits etc.

Look at a map, get to know where all the 53 countries in Africa are.  Get to know which are prosperous.

in Egypt there are very white Egyptians... you would fit right in

Skin colour is irrelevant. 

If you want to get a job in a specific African country, you'll need to investigate the work visa for that specific African country; and then successfully apply for said work visa. Very few countries allow for part time work visas.

If you're going to the country primarily to study, you'll need to check what (if any) provision there is for working on your student visa. Most countries prohibit or limit work on a student visa (and many students even where it's allowed never find work; you have to fund your studies before you get the visa)

Bear in mind EARNINGS in many African countries are $300-900 A YEAR. Unless you are in high demand, a student would probably earn the same.

EDIT: As for STUDY, Africans come to Russia to study in the universities because OURS ARE BETTER AND CHEAPER (I have asked several Africans I have seen in Russia thru the years. Nigerians, Kenyans and The Gambians are countries which come to mind). So it may hit you hard in the pocketbook.

A good starting point would be remembering that Africa is not a country, but instead a continent.  If you want any sort of real answer, then narrow this question down to a single nation.