What's wrong with my 454 GMC Motorhome?

yes something is stuck in the carb like the float, possibly from old gas, smell the oil see if it smells like gas too, but chances are with gas pouring out the carb, you need to take the carb off and either rebuild it yourself, have it rebuilt, or better yet put a brand new carb on, which is the choice I would make, it will be more efficient, and get better mileage, and last a long time. if the oil smells like gas, you need to dump the oil and change it, but dont run the motor home intil you fix the carb problem, someone with some experience can fix the carb, the problem is once you take it apart, it needs to be rebuilt anyway.