diff --git a/lisp/help-mode.el b/lisp/help-mode.el
index 94bd591131..4ad8e36070 100644
--- a/lisp/help-mode.el
+++ b/lisp/help-mode.el
@@ -414,6 +414,13 @@ help-mode
   (setq-local tool-bar-map
               help-mode-tool-bar-map)
   (setq-local help-mode--current-data nil)
+  (unless search-default-mode
+    (setq-local search-default-mode
+                (lambda (string &optional _lax)
+                  (thread-last
+                    (regexp-quote string)
+                    (replace-regexp-in-string "`" "[`‘]")
+                    (replace-regexp-in-string "'" "['’]")))))
   (setq-local bookmark-make-record-function
               #'help-bookmark-make-record))
 
diff --git a/lisp/info.el b/lisp/info.el
index abfb77b055..7e0d4f646f 100644
--- a/lisp/info.el
+++ b/lisp/info.el
@@ -4487,6 +4487,14 @@ Info-mode
   (setq-local isearch-wrap-function #'Info-isearch-wrap)
   (setq-local isearch-push-state-function #'Info-isearch-push-state)
   (setq-local isearch-filter-predicate #'Info-isearch-filter)
+  (unless search-default-mode
+    (setq-local search-default-mode
+                (lambda (string &optional _lax)
+                  (thread-last
+                    (regexp-quote string)
+                    (replace-regexp-in-string "`" "[`‘]")
+                    (replace-regexp-in-string "'" "['’]")
+                    (replace-regexp-in-string "\"" "[\"“”]")))))
   (setq-local revert-buffer-function #'Info-revert-buffer-function)
   (setq-local font-lock-defaults '(Info-mode-font-lock-keywords t t))
   (Info-set-mode-line)