Re: how to use the choke
I picked up on two things you said. One was "when I run the choke for awhile". How long is awhile? Running with the choke open for too long will actually flood the engine. You should never need the choke for more than 15-20 seconds, and that's usually in cooler temperatures. In warmer temperatures, 5-10 seconds if at all. The other thing I picked up on was "bring the choke to half". A carb that is properly installed and sealed with no leaks or cracks anywhere should run smoothly with the choke all the way off (open). A carb that is tuned very lean may run better with some choke, but the NT carbs usually don't come lean stock. If you're in Death Valley or somewhere else way below sea level, the stock tuning might be a little lean due to the increased air pressure, but if you're at or above sea level, the stock tuning should definitely not be lean, so if you haven't leaned out your carb at all, then it should be able to run smoothly with no choke (once warmed up), provided that the carb is properly sealed to the intake and has no cracks. Remember like Tom said, when the lever is down the choke is open, and when it's up the choke is closed. You want to close the choke to let the engine warm up, then open it to let the engine run smoothly once warmed up.