Index: Lib/email/encoders.py
===================================================================
--- Lib/email/encoders.py	(revision 80709)
+++ Lib/email/encoders.py	(working copy)
@@ -72,13 +72,7 @@
     try:
         orig.encode('ascii')
     except UnicodeError:
-        # iso-2022-* is non-ASCII but still 7-bit
-        charset = msg.get_charset()
-        output_cset = charset and charset.output_charset
-        if output_cset and output_cset.lower().startswith('iso-2022-'):
-            msg['Content-Transfer-Encoding'] = '7bit'
-        else:
-            msg['Content-Transfer-Encoding'] = '8bit'
+        msg['Content-Transfer-Encoding'] = '8bit'
     else:
         msg['Content-Transfer-Encoding'] = '7bit'
 
Index: Lib/email/test/test_email.py
===================================================================
--- Lib/email/test/test_email.py	(revision 80709)
+++ Lib/email/test/test_email.py	(working copy)
@@ -564,6 +564,12 @@
         msg = MIMEText('hello \xf8 world', _charset='iso-8859-1')
         eq(msg['content-transfer-encoding'], 'quoted-printable')
 
+    def test_encode7or8bit(self):
+        eq = self.assertEqual
+        # test for iso-2022-*
+        msg = email.MIMEText.MIMEText('\xca\xb8', _charset='euc-jp')
+        email.encoders.encode_7or8bit(msg)
+        eq(msg['content-transfer-encoding'], '7bit')
 
 
 # Test long header wrapping