diff --git a/lisp/nnir.el b/lisp/nnir.el
index 2a264d1..a6a561e 100644
--- a/lisp/nnir.el
+++ b/lisp/nnir.el
@@ -1606,7 +1606,10 @@ and concat the results."
 			       search-func)
 			   (setq search-func (cadr
 					      (assoc
-					       (nnir-read-server-parm 'nnir-search-engine server) nnir-engines)))
+					       (or (nnir-read-server-parm
+						    'nnir-search-engine server)
+						   (when (eq 'nnimap (car
+								      (gnus-server-to-method server))) 'imap)) nnir-engines)))
 			   (if search-func
 			       (funcall search-func q server x)
 			     nil)))
@@ -1617,9 +1620,12 @@ and concat the results."
 		       (if (and (equal (cadr x) 'ok) (not (equal (cadar x) "-ephemeral")))
 			   (let ((server (format "%s:%s" (caar x) (cadar x)))
 				 search-func)
-			     (setq search-func (cadr
-						(assoc
-						 (nnir-read-server-parm 'nnir-search-engine server) nnir-engines)))
+			   (setq search-func (cadr
+					      (assoc
+					       (or (nnir-read-server-parm
+						    'nnir-search-engine server)
+						   (when (eq 'nnimap (car
+								      (gnus-server-to-method server))) 'imap)) nnir-engines)))
 			     (if search-func
 				 (funcall search-func q server nil)
 			       nil))