--- a/mailnews/test/resources/asyncTestUtils.js
+++ b/mailnews/test/resources/asyncTestUtils.js
@@ -230,20 +230,20 @@ function _async_test_runner_timeout() {
  *  to run the test once for each element in the aParameters list.  If the
  *  elements in the aParameters list have a 'name' attribute, it will get
  *  printed out to help figure out what is actually happening.
  */
 function parameterizeTest(aTestFunc, aParameters) {
   return [aTestFunc, aParameters];
 }
 
-// This time is 10 seconds less than the tinderbox timeout default of 300
+// This time is 60 seconds less than the tinderbox timeout default of 300
 // seconds and will hopefully cause tests to give us their logs before that
 // timeout.
-const DEFAULT_LONGEST_TEST_RUN_CONCEIVABLE_SECS = 290;
+const DEFAULT_LONGEST_TEST_RUN_CONCEIVABLE_SECS = 240;
 function async_run_tests(aTests, aLongestTestRunTimeConceivableInSecs) {
   if (aLongestTestRunTimeConceivableInSecs == null)
     aLongestTestRunTimeConceivableInSecs =
         DEFAULT_LONGEST_TEST_RUN_CONCEIVABLE_SECS;
   do_timeout(aLongestTestRunTimeConceivableInSecs * 1000,
       _async_test_runner_timeout);
 
   do_test_pending();