diff --git a/src/timer.cpp b/src/timer.cpp
index c6f6401799..667c0e8946 100644
--- a/src/timer.cpp
+++ b/src/timer.cpp
@@ -15,6 +15,7 @@
 
 #include "comm.h"
 #include "error.h"
+#include "tokenizer.h"
 #include "fmt/chrono.h"
 
 #include <cstring>
@@ -231,9 +232,14 @@ void Timer::modify_params(int narg, char **arg)
     } else if (strcmp(arg[iarg], "timeout") == 0) {
       ++iarg;
       if (iarg < narg) {
-        _timeout = utils::timespec2seconds(arg[iarg]);
-      } else
-        error->all(FLERR, "Illegal timer command");
+        try {
+          _timeout = utils::timespec2seconds(arg[iarg]);
+        } catch (TokenizerException &) {
+          error->all(FLERR, "Illegal timeout time: {}", arg[iarg]);
+        }
+      } else {
+        utils::missing_cmd_args(FLERR, "timer timeout", error);
+      }
     } else if (strcmp(arg[iarg], "every") == 0) {
       ++iarg;
       if (iarg < narg) {
diff --git a/src/utils.cpp b/src/utils.cpp
index 59984c8443..0f5b50baf2 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -1744,13 +1744,9 @@ double utils::timespec2seconds(const std::string &timespec)
 
   ValueTokenizer values(timespec, ":");
 
-  try {
-    for (i = 0; i < 3; i++) {
-      if (!values.has_next()) break;
-      vals[i] = values.next_double();
-    }
-  } catch (TokenizerException &) {
-    return -1.0;
+  for (i = 0; i < 3; i++) {
+    if (!values.has_next()) break;
+    vals[i] = values.next_double();
   }
 
   if (i == 3)