RE: h9 1/3 cap zdz 80 comments/questions
J, IF everything is rite on the engine you should only have to choke the first start of the day. If you have to choke every time, check to see if the fuel runs out of the fuel line at the carb, requireing you to reprime the carb. You may have a leak.
If the plug is tan your engine is probably running lean. My 80 has a little carbon buildup on the plug.
Your midrange throttle is set with the low end needle.
To set the high end you need two things. A tachomiter, and the help of a friend (if possible). Run the engine at WOT, lrt it clean out, then get an RPM reading. The goal is to either lean or richen the engine for max RPM. When you get that set, richen the top end around a 1/4 turn. This will lower your max RPM by about 200 (in most cases). Now that that is set you can go to work on the low end needle. All you are looking to get here is a smoothe transition from idle to WOT. If you lean the low end to much you will overheat the engine and you will not be happy with the possible results (flameout to crash). The transition doesn't have to be like a racecar, It just has to be smoothe, no bogs or misses.
If all you have in your area is 91 octane you will be fine. You are tuneing the engine to run on the fuel you have.
My engine start is choke on, flip 6-8 times. Choke off, ignition on flip 1-3 times to start. If yours takes that many flips you may not have fuel to start (lean low end needle).
Your RPM sounds about rite. Kill the engine when you adjust the needles. Much safer that way. Good luck. I hope this will help. Ron