will not stay running already replaced plugs
vacuum hose maybe

 

Need more information please.

 

Welcome Deborah. You will find the more history and info you give use, the more help you will receive. "Will not stay running" could generate about a thousand item list of possibilities!

 

For sure could be a vacuum leak, not just hoses but accessories like brake booster etc. too.

Also look at carb, choke. Are you starting it with starting fluid or on its own? What carb is it?

What happens if you feather the gas or adjust the idle up?

When did this start happening? does it coincide with any other repairs that may have been done?