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Black smoke

I have black smoke coming out of my muffler… What am I burning?

While a definitive answer really requires that you identify the make, model, model year, engine type, and odometer mileage of this mystery vehicle, I will give you a general answer:

Black smoke is usually an indication that your engine is running on too “rich” a mixture of gasoline and air, or to put it in more basic terms–too much gas and not enough air is being burned in the cylinders. If this vehicle is old enough to be carbureted, rather then fuel injected, this is not that unusual. On the other hand, if the engine is fuel injected, this is unusual.

Some additional information that we need is as follows:
Is this mystery vehicle up to date with its maintenance?
Has your gas mileage decreased recently?
Is the engine idling roughly?
Is the Check Engine Light (CEL) illuminated?

Also, is it diesel or gas powered?

Yes, if it’s a diesel, that could lead down a different diagnostic path.
Generally speaking in gasoline engines:
Black smoke is almost always fuel.
Blue-Grey is most always oil.
White is usually steam, a sign that coolant is making its way from
the cooling jacket – via a gasket or head/block crack – into the
combustion chamber.
It’ll be interesting,seeing how the original question was posed, to see if the OP ever returns…

If you have an 82 Accord, I might have an answer.

Would that answer be a leaky carb float valve?

You are burning gasoline – a lot of it – and very poorly. Have the choke linkage cleaned up and adjusted and the choke pulloff checked.

As happens so often, it seems that we are more interested in giving helpful advice than the OP is in receiving it. Either the OP has not returned, or he/she has decided to not respond to my attempts to get more information.