Hi. I'd like to make a few suggestions.. It's important that the idle speed screw is at the right setting or the choke mechanism doesn't work properly. The choke doesn't actually choke off the air supply as a butterfly type does. In the carbys with the plunger, the plunger being lifted when you put the choke on is meant to let extra air and fuel through a separate passage to assist with cold starting. That won't work though if the throttle is open, or the idle is set too high. The choke has to have good vacuum to suck the fuel up high to that plunger, and through that extra passage, and it can't do that if the throttle is too far open lowering the vacuum. So don't give it throttle while you're trying to enrichen it for starting, that stops the choke/enrichener from working, as does having the idle speed wound up too high. With a conventional butterfly choke that doesn't apply and you can give it throttle while the choke is on and it will still deliver extra fuel.. but not with the plunger ones. If the choke/enrichener doesn't seem to be working, try winding the idle speed screw out a little.. count the turns so you can set it back again if it's not the problem. That often gets them firing and then you can slowly open the throttle to get them to start. Secondly, there are two types of idle mixture screw setups. If the idle mixture screw is near the inlet manifold, as most suzukis are, then its cutting off the fuel as you wind it in, making the mixture leaner. In the other setup the idle mixture screw is near the air-cleaner end of the carby and as you screw those in they cut off the air supply to the idle mixture making it richer. This applies whether the screw is underneath or on the side of the carby. If it's near the engine it's cutting the fuel off, making it leaner, and if it's near the air-cleaner it's cutting the air to the idle mixture off making it richer. Hope that helps with the understanding what's going on.