A trick I recently borrowed from a YouTube video, that works pretty well on my 235: Rather than trying to dance between idle mixture, idle speed, and timing when doing a tune up….
….Use a vac gauge hooked to the ported vacuum to set the idle speed. Adjust idle speed screw until you just barely start to see vacuum at the gauge. Then leave it alone. Takes one variable out of play. It’s pretty easy to get too aggressive with the idle speed screw, and then you aren’t getting the proper response from idle mixture or timing adjustments.
Then use timing and idle mixture to optimize idle speed, quality, throttle response, and vac reading.
You can also do this by just eyeballing that port with the carb off an upside down, this is just simpler if the carb is already mounted.
