diff --git a/sphinx/builders/html.py b/sphinx/builders/html.py
index 6e8279f7c..a99d50d58 100644
--- a/sphinx/builders/html.py
+++ b/sphinx/builders/html.py
@@ -696,7 +696,10 @@ class StandaloneHTMLBuilder(Builder):
             return uri
         ctx['pathto'] = pathto
         ctx['hasdoc'] = lambda name: name in self.env.all_docs
-        ctx['encoding'] = encoding = self.config.html_output_encoding
+        if self.name != 'htmlhelp':
+            ctx['encoding'] = encoding = self.config.html_output_encoding
+        else:
+            ctx['encoding'] = encoding = self.encoding
         ctx['toctree'] = lambda **kw: self._get_local_toctree(pagename, **kw)
         self.add_sidebars(pagename, ctx)
         ctx.update(addctx)
diff --git a/sphinx/builders/htmlhelp.py b/sphinx/builders/htmlhelp.py
index f5d716d98..79c2e6058 100644
--- a/sphinx/builders/htmlhelp.py
+++ b/sphinx/builders/htmlhelp.py
@@ -258,8 +258,8 @@ class HTMLHelpBuilder(StandaloneHTMLBuilder):
             def write_index(title, refs, subitems):
                 def write_param(name, value):
                     item = '    <param name="%s" value="%s">\n' % (name, value)
-                    f.write(item.encode('ascii', 'xmlcharrefreplace')
-                            .decode('ascii'))
+                    f.write(item.encode(self.encoding, 'xmlcharrefreplace')
+                            .decode(self.encoding))
                 title = cgi.escape(title)
                 f.write('<LI> <OBJECT type="text/sitemap">\n')
                 write_param('Keyword', title)
diff --git a/sphinx/pycode/pgen2/driver.py b/sphinx/pycode/pgen2/driver.py
index 39e347b79..5e6cf9a5b 100644
--- a/sphinx/pycode/pgen2/driver.py
+++ b/sphinx/pycode/pgen2/driver.py
@@ -120,7 +120,7 @@ def load_grammar(gt="Grammar.txt", gp=None,
         head, tail = os.path.splitext(gt)
         if tail == ".txt":
             tail = ""
-        gp = head + tail + ".".join(map(str, sys.version_info)) + ".pickle"
+        gp = head + tail + ".".join(map(str, sys.version_info[:2])) + ".pickle"
     if force or not _newer(gp, gt):
         logger.info("Generating grammar tables from %s", gt)
         g = pgen.generate_grammar(gt)