i have a friend with an 87 camaro 305 carb (lg4?) hees blowing black smoke pretty bad i think hees running rich so i told him not to drive it cause he will ruin his rings its never been rebuilt and has 100xxx miles i was thinking he might need a carb rebuild or atleast a air/fuel adjustment but im not too carb savvy so i figured id ask here any suggestions????

 

First things first: Is the check engine light on? If so, see what code it has set.

I wouldn't be surpirsed if it's the O2 sensor. When they go bad, the computer goes into a rich condition. Could also be flooding, caused by debris in the float valve needle/seat, bad needle/seat, or bad float. Q-jets also are known for leaking lead plugs under the float bowl, which allows fuel to go directly to the intake manifold instead of being metered like its supposed to be.

Could also be an ignition problem - bad coil, bad ignition control module come to mind. That is typically combined with poor idle/missing/poor power.