Terry,
I used just plain old engine oil to flush it out first.
First put a heap in it and then shake it around a bit.
Drain it and then fill using a good quality semi synthetic oil like Penrite.
These little air cooled motors run hard, fast, and hot. LOL
Start it up with a garden hose running up the suction spigot on the pump and let it run with a bit of throttle for 5 minutes then shut her down and drain it out.
Refill with fresh oil then run it for the first few hours as you would.
drain the oil after warming it up using the garden hose method then change the oil again.
You can now extend into a good days use but change the oil after about two to 3 tank fulls of fuel.
After about 4 tanks of fuel you can consider it running as normal keep regular maintenance up like change the oil at the regular intervals, Check and clean the
air filter after about every 2 tank fulls of fuel.
I would highly recommend carrying some spare spark plugs, NGK and some replacement starter cord and learn how to replace them both in the field.
This to me is standard practice and if followed will give you piece of mind that you will get at least enough out of it until you can replace it for another.
You might get years out of it but remember it is a "Low End Product". I mean no offense at that but look at the whole picture.
I have done the same thing. PMSL