RE: What kind of fuel to use?
G'day
Hmmm, Which Enya 45? Some have AAC setups (Aluminium Liner, Aluminium Piston and liner is Chromed) the CX-45 is like this and I have one of them but some of the older ones used iron pistons with steel liners and they need castor. Some are plain bearing and they need castor too.
Do you have a photo? It would help to identify the engine and so its preferred diet.
In general, ABC and AAC engines with ball bearing crank shafts are fine with synthetic oil but the older iron/steel engines need castor and especially if they are plain bearing (bushed) engines.