345 Engine Problem

[JDMainer]

I have a 345 with a 20 hp kaw engine. I ran out of gas the other day, since then it is only running on one cylinder. Already changed the plugs...what next?

 

[Molerj]

How did you determine it is running on one cylinder? Running out of gas would not affect your spark. Do you think it is running rough because some dirt got sucked into the carb?