diff --git a/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/FanoutReplicationConfig.java b/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/FanoutReplicationConfig.java
index 412c2ff..4a3bc4b 100644
--- a/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/FanoutReplicationConfig.java
+++ b/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/FanoutReplicationConfig.java
@@ -54,12 +54,19 @@
             FS.DETECTED);
 
     replicationConf.load();
-    replicationConf.setString("remote", null, "url", url);
+    String currentUrl = replicationConf.getString("remote", null, "url");
+    if (currentUrl == null) {
+      replicationConf.setString("remote", null, "url", url);
+    }
     List<String> projects =
         new ArrayList<>(Arrays.asList(replicationConf.getStringList("remote", null, "projects")));
     projects.add(projectName);
     replicationConf.setStringList("remote", null, "projects", projects);
-    replicationConf.setString("remote", null, "push", "refs/*:refs/*");
+
+    String currentPushRefs = replicationConf.getString("remote", null, "push");
+    if (currentPushRefs == null) {
+      replicationConf.setString("remote", null, "push", "refs/*:refs/*");
+    }
     replicationConf.save();
   }
 }
diff --git a/github-plugin/src/test/java/com/googlesource/gerrit/plugins/github/FanoutReplicationConfigTest.java b/github-plugin/src/test/java/com/googlesource/gerrit/plugins/github/FanoutReplicationConfigTest.java
new file mode 100644
index 0000000..3613c41
--- /dev/null
+++ b/github-plugin/src/test/java/com/googlesource/gerrit/plugins/github/FanoutReplicationConfigTest.java
@@ -0,0 +1,99 @@
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.github;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.gerrit.server.config.SitePaths;
+import com.googlesource.gerrit.plugins.github.git.FanoutReplicationConfig;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import org.apache.commons.io.FileUtils;
+import org.eclipse.jgit.storage.file.FileBasedConfig;
+import org.eclipse.jgit.util.FS;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+public class FanoutReplicationConfigTest {
+
+  private static final String CUSTOM_KEY = "mykey";
+  private static final String CUSTOM_VALUE = "myvalue";
+  private static final String REMOTE_ENDPOINT = "my-remote-endpoint";
+  private static final String TEST_REMOTE_URL = "http://github.com/myurl";
+  private static final String TEST_PROJECT_NAME = "myprojectname";
+  private Path tempDir;
+  private SitePaths sitePaths;
+
+  @Before
+  public void setup() throws Exception {
+    tempDir = Files.createTempDirectory(getClass().getSimpleName());
+    sitePaths = new SitePaths(tempDir);
+    Files.createDirectories(sitePaths.etc_dir);
+  }
+
+  @After
+  public void teardown() throws Exception {
+    FileUtils.deleteDirectory(tempDir.toFile());
+  }
+
+  @Test
+  public void shoudKeepAdHocSettingsInFanoutReplicationConfig() throws Exception {
+    FileBasedConfig currConfig = getReplicationConfig();
+    currConfig.setString("remote", null, CUSTOM_KEY, CUSTOM_VALUE);
+    currConfig.save();
+
+    String url = "http://github.com/myurl";
+    FanoutReplicationConfig fanoutReplicationConfig = new FanoutReplicationConfig(sitePaths);
+    fanoutReplicationConfig.addReplicationRemote(REMOTE_ENDPOINT, url, "myproject");
+
+    currConfig.load();
+    assertThat(currConfig.getString("remote", null, CUSTOM_KEY)).isEqualTo(CUSTOM_VALUE);
+  }
+
+  @Test
+  public void shoudKeepCustomUrlInFanoutReplicationConfig() throws Exception {
+    FileBasedConfig currConfig = getReplicationConfig();
+    String customUrl = "http://my-custom-url";
+    currConfig.setString("remote", null, "url", customUrl);
+    currConfig.save();
+
+    new FanoutReplicationConfig(sitePaths)
+        .addReplicationRemote(REMOTE_ENDPOINT, TEST_REMOTE_URL, TEST_PROJECT_NAME);
+
+    currConfig.load();
+    assertThat(currConfig.getString("remote", null, "url")).isEqualTo(customUrl);
+  }
+
+  @Test
+  public void shoudKeepCustomPushRefSpecInFanoutReplicationConfig() throws Exception {
+    FileBasedConfig currConfig = getReplicationConfig();
+    String customPushRefSpec = "+refs/heads/myheads/*:refs/heads/myheads/*";
+    currConfig.setString("remote", null, "push", customPushRefSpec);
+    currConfig.save();
+
+    new FanoutReplicationConfig(sitePaths)
+        .addReplicationRemote(REMOTE_ENDPOINT, TEST_REMOTE_URL, TEST_PROJECT_NAME);
+
+    currConfig.load();
+    assertThat(currConfig.getString("remote", null, "push")).isEqualTo(customPushRefSpec);
+  }
+
+  private FileBasedConfig getReplicationConfig() {
+    return new FileBasedConfig(
+        sitePaths.etc_dir.resolve("replication").resolve(REMOTE_ENDPOINT + ".config").toFile(),
+        FS.DETECTED);
+  }
+}