Morning Bondy and Mark,
Bondy, It sounds like the choke isn't closing on start. Sounds to me like you aren't getting full travel with the throttle lever/cable. This accounting for both the starting and stopping problems. I had the exact same problem when I fitted a Honda to my Greenie a couple years ago- starting was difficult. I took the air cleaner assembly off to physically sight the choke to see what was happening. It only closes at the very, very end of the lever travel. In my case the cable travel and lever slot cut into the panel were the limiting things. If I adjusted it a poofteenth too far, it wouldn't cut off in the stop position (not hitting the magneto kill contacts). A poofteenth the other way and I had no choke. My guess is you have neither.
To prove the fault I disconnected the cable at the engine and tried starting and stopping it with the lever on the engine.
They tell us it will be cooler after today
