I have my Dad's 87 Dodge Dakota that he purchased new in 1987. It's been a long restoration process and the truck sits idle for long periods (about 3 months) at a time. I had it running earlier this summer but now if I try run it , it seems to be very rich mixture wise.

If I pull a vacuum line, it seems to run better, like adding more air helps it.

It's all stock. The carb and engine were rebuilt 4 years ago. No mods done on it. Any thing I should try from a diagnostic stand point? My only concern is that I have stale gas that is causing this condition. It does start and run on the first try.

 

It could be bad gas due to letting it sit or just a gummed up carb due to the same reason.