exhaust problem?

[Zhang]

I found the exhaust of my 87 Volvo becomes black, what kind of problem does
this suggest?

Thank you!

 

[Peter Milnes]

Your engine is running way too over-rich.

Cheers, Peter.

: I found the exhaust of my 87 Volvo becomes black, what kind of problem does
: this suggest?
:
: Thank you!
:
:

 

[Dale Albiston]

Your engine is running way too over-rich.

Cheers, Peter.

: I found the exhaust of my 87 Volvo becomes black, what kind of problem
: does this suggest?
:
: Thank you!
:
:

Mine also does this, how to you adjust it? I remember something to do with
the carb but not what (been years since I played with one)