diff --git a/m2_kernel/kernel.py b/m2_kernel/kernel.py
index 7914bae..568ce80 100644
--- a/m2_kernel/kernel.py
+++ b/m2_kernel/kernel.py
@@ -82,7 +82,7 @@ def start(self):
         if not (self.proc is None):
             return
         self.proc = pexpect.spawn(self.proc_command, **self.proc_kwargs)
-        self.proc.delaybeforesend = None
+        self.proc.delaybeforesend = 0
 
     def preprocess(self, code, usemagic, printwidth=80):
         """"""