RE: ZDZ 80 Hard to start
What did you change from and to?
What mix ratio?
Any needle changes?
I too am running that same oil in my OLDER (4 year old) ZDZ 80 at 32:1.
I have had success in starting it this way.
Ingnition on, choke on, couple clicks above idle, flip till pops, choke off and about 10-15 flips you can here it poping again, 5 or so flips after that and running.
You will get tons of ways to start an engine, this is what works for me.
I also have a ZDZ Blue Head and start it the same way, but it starts in about 5 flips after hearing it pop.
PS:
I have recently sold both planes that these where on.
Great engines.
Good luck and lets us know.