diff --git a/lib/puppet/util/ini_file.rb b/lib/puppet/util/ini_file.rb
index b7529812..dc84c7d2 100644
--- a/lib/puppet/util/ini_file.rb
+++ b/lib/puppet/util/ini_file.rb
@@ -63,6 +63,7 @@ def set_value(*args)
       when 3
         # Backwards compatible set_value function, See MODULES-5172
         (section_name, setting, value) = args
+        separator = @key_val_separator
       when 4
         (section_name, setting, separator, value) = args
       end