I downloaded a wt&balance ap for the M20R and it works great.  However, they indicate a 'zero fuel weight' number in the envelope.  I have been unable to find any reference to a 'zero fuel weight' limit in the POH.  I am accustomed to dealing with this limit with jet aircraft but have found no reference in the M20R manual.  Is there a 'zero fuel weight' limit on the M20R?