diff --git a/searx/engines/qwant.py b/searx/engines/qwant.py
index cee2dfa975903c0a50969de5b8ccecb35c3a612f..e2ac19465662ee551e290c60e2275668e291b6ac 100644
--- a/searx/engines/qwant.py
+++ b/searx/engines/qwant.py
@@ -93,6 +93,8 @@ def request(query, params):
             supported_languages,
             language_aliases,
         )
+        if language not in supported_languages:
+            language = 'en-US'
         params['url'] += '&locale=' + language.replace('-', '_')
 
     params['raise_for_httperror'] = False
diff --git a/searx/settings.yml b/searx/settings.yml
index 2057c4dd87e08d58a42464e2f2052a108d507d20..c0568975966d394926eef59c932f3af5c27fae5a 100644
--- a/searx/settings.yml
+++ b/searx/settings.yml
@@ -412,7 +412,7 @@ engines:
   - name: wikidata
     engine: wikidata
     shortcut: wd
-    timeout: 3.0
+    timeout: 6.0
     weight: 2
     tests: *tests_infobox
 
@@ -589,6 +589,7 @@ engines:
   - name : google images
     engine : google_images
     shortcut : goi
+    timeout: 6.0
     # additional_tests:
     #   android: *test_android
     #   dali:
@@ -741,19 +742,11 @@ engines:
 
   - name : invidious
     engine : invidious
-    base_url :
-      - https://invidious.tube/
-      - https://invidious.snopyta.org/
+    base_url : https://invidious.weblibre.org/
     shortcut: iv
     timeout : 5.0
     disabled : True
 
-  - name: kickass
-    engine : kickass
-    shortcut : kc
-    timeout : 4.0
-    disabled : True
-
   - name : library genesis
     engine : xpath
     paging : True
diff --git a/searx/webapp.py b/searx/webapp.py
index 5a0f279a48c35cc11bfdee25c5ac54e9e39ee73f..2d5c780b6bb22013ffbd9be4fe7c16bb899e0417 100755
--- a/searx/webapp.py
+++ b/searx/webapp.py
@@ -619,7 +619,7 @@ def search():
 
     # output_format
     output_format = request.form.get('format', 'html')
-    if output_format not in ['html', 'csv', 'json', 'rss']:
+    if output_format not in ['html', 'rss']:
         output_format = 'html'
 
     # check if there is query (not None and not an empty string)
diff --git a/tests/unit/test_webapp.py b/tests/unit/test_webapp.py
index 92f6bb119710c4d284c87d35db1ae3aa0d529b34..e67093d8996cfdaee464fdb89d9633c485efc404 100644
--- a/tests/unit/test_webapp.py
+++ b/tests/unit/test_webapp.py
@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 
-import json
 from urllib.parse import ParseResult
 from mock import Mock
 from searx.testing import SearxTestCase
@@ -98,14 +97,6 @@ class ViewsTestCase(SearxTestCase):
         self.assertEqual(result.status_code, 200)
         self.assertIn(b'<span class="instance pull-left"><a href="/">Spot</a></span>', result.data)
 
-    def test_search_empty_json(self):
-        result = self.app.post('/search', data={'q': '', 'format': 'json'})
-        self.assertEqual(result.status_code, 400)
-
-    def test_search_empty_csv(self):
-        result = self.app.post('/search', data={'q': '', 'format': 'csv'})
-        self.assertEqual(result.status_code, 400)
-
     def test_search_empty_rss(self):
         result = self.app.post('/search', data={'q': '', 'format': 'rss'})
         self.assertEqual(result.status_code, 400)
@@ -124,33 +115,6 @@ class ViewsTestCase(SearxTestCase):
             result.data
         )
 
-    def test_index_json(self):
-        result = self.app.post('/', data={'q': 'test', 'format': 'json'})
-        self.assertEqual(result.status_code, 308)
-
-    def test_search_json(self):
-        result = self.app.post('/search', data={'q': 'test', 'format': 'json'})
-        result_dict = json.loads(result.data.decode())
-
-        self.assertEqual('test', result_dict['query'])
-        self.assertEqual(len(result_dict['results']), 2)
-        self.assertEqual(result_dict['results'][0]['content'], 'first test content')
-        self.assertEqual(result_dict['results'][0]['url'], 'http://first.test.xyz')
-
-    def test_index_csv(self):
-        result = self.app.post('/', data={'q': 'test', 'format': 'csv'})
-        self.assertEqual(result.status_code, 308)
-
-    def test_search_csv(self):
-        result = self.app.post('/search', data={'q': 'test', 'format': 'csv'})
-
-        self.assertEqual(
-            b'title,url,content,host,engine,score,type\r\n'
-            b'First Test,http://first.test.xyz,first test content,first.test.xyz,startpage,,result\r\n'  # noqa
-            b'Second Test,http://second.test.xyz,second test content,second.test.xyz,youtube,,result\r\n',  # noqa
-            result.data
-        )
-
     def test_index_rss(self):
         result = self.app.post('/', data={'q': 'test', 'format': 'rss'})
         self.assertEqual(result.status_code, 308)