"Steve...
There may a slight
"Steve...
There may a slight bit more going on than meets the eye....but not too much more. If the engine used to start and idle fine, but it doesn't idle anymore, there must be a reason for that. Cranking around on a carb screw just masks the problem. I wouldn't play around too much with the mixture screw at this point. You may have a varnish/gum-up problem going on. I'd try spraying some carb cleaner down the barrel of the carb to soften things up in there. Start it up and give it some more while it's running. Don't flood it too much while its running or risk the whole hydraulic lock up syndrome. Throw some fuel injector cleaner in the gas tank just as you would in your car and let that start working from that end. If the mixture screw is easy to get at, take it out (engine off), counting the number of turns it takes to get it out, and spray some cleaner into the screw hole to clean that up. Re-install the screw, counting the turns, and see how it goes. Don't crank that screw too far in to cause a lean-pop problem. That raises cyl. head temps and that leads to a whole other set of problems. If it doesn't start getting better, then turn up the idle speed screw a little and keep your eye on it if it starts to run too fast in the future.
OMC has tune-up cleaner to use for it or try Seafoam. If not get some regular auto carb cleaner.
Wrench"
