diff --git a/tests/main.rs b/tests/main.rs
index 2638ae4f..3b0b84a3 100644
--- a/tests/main.rs
+++ b/tests/main.rs
@@ -745,7 +745,7 @@ fn mutants_causing_tests_to_hang_are_stopped_by_manual_timeout() {
     // Also test that it accepts decimal seconds
     let out = run()
         .arg("mutants")
-        .args(["-t", "8.1", "--build-timeout-multiplier=3"])
+        .args(["-t", "8.1", "--build-timeout=15.5"])
         .current_dir(tmp_src_dir.path())
         .env_remove("RUST_BACKTRACE")
         .timeout(OUTER_TIMEOUT)