The MotionMail timer is simply an image tag, so you can center it the same way way you center other images in your email template. You can either do this through the tools your email marketing platform might provide, or using CSS by following the instructions here: https://www.w3.org/Style/Examples/007/center.en.html#block
Other tips to center you timer include:
To center the image you can add a style attribute around the embed code like this: <p style="text-align:center;"><Embed Code></p>
or
You can also use <center><embed code></center> center tags.
MailChimp Users:
If you followed the instructions in our article here: How do I add a Countdown Timer to MailChimp? and your code looks like this:
<div class="mcnImage">
<img src="http://embedcode" alt="motionmailapp.com" style="width:100%; height:auto;" />
</div>
You can just add the bolded center tags around the code.
<div class="mcnImage">
<center>
<img src="http://embedcode" alt="motionmailapp.com" style="width:100%; height:auto;" />
</center>
</div>