diff --git a/submission_runner.py b/submission_runner.py
index 717ea2dc4..47730d3fc 100644
--- a/submission_runner.py
+++ b/submission_runner.py
@@ -340,9 +340,12 @@ def train_once(
 
     train_state['accumulated_submission_time'] += (
         train_step_end_time - train_state['last_step_end_time'])
+    # Use 3x the runtime budget for the self-tuning ruleset.
+    max_allowed_runtime_sec = (
+        workload.max_allowed_runtime_sec if FLAGS.tuning_ruleset == 'external'
+        else 3 * workload.max_allowed_runtime_sec)
     train_state['is_time_remaining'] = (
-        train_state['accumulated_submission_time'] <
-        workload.max_allowed_runtime_sec)
+        train_state['accumulated_submission_time'] < max_allowed_runtime_sec)
     # Check if submission is eligible for an untimed eval.
     if ((train_step_end_time - train_state['last_eval_time']) >=
         workload.eval_period_time_sec or train_state['training_complete']):
@@ -567,6 +570,9 @@ def score_submission_on_workload(workload: spec.Workload,
       logging.info(f'Total number of evals: {num_evals}')
       logging.info('=' * 20)
   else:
+    if tuning_search_space is not None:
+      raise ValueError(
+          'Cannot provide a tuning search space when using self tuning.')
     if not rng_seed:
       rng_seed = struct.unpack('q', os.urandom(8))[0]
     rng = prng.PRNGKey(rng_seed)