I would'nt use a Moki it will be way to heavy for the excelleron. As far as i know MOKI will not be imported anymore. Morris hobbies now sells Mark engines that are made in the same place just a different name? As far as a engine for the excelleron i would use a YS 110 or something in the same weight range. I have a MOKI 1.35 I had it in a edge 540 about 11lb. plane. Your excelleron should be around 9 lbs. or less probably 8.5 lbs.