RE: ZDZ 80 Hard to start
Actually just about every ZDZ I have ever started for someone else (never owned one myself went like this and it seems to work everytime
it's the old 5-5-1 rule
Ignition off, full choke, full throttle 5 flips
Ignition off, full choke, no throttle 5 flips (gets the engine good and wet)
Ignition on, no choke, throttle to idle, one flip and she's running.
This all assumes you do not have the low needle too lean which is what it sounds like or even the choke is not closing completely