Hey Guys, I just finished up putting a XL12 SDC carburetor on one of my 3.7 Ropers/Craftsmen saws. Because the idle screw is in the way of the high speed adjustment screw, I wound up cutting the high speed screw down about a half inch so it would fit under the throttle arm and cut a groove so a screwdriver would fit it. You might consider drilling a whole in the throttle arm to adjust it while running. I just turn the saw off, open the trigger and make an adjustment, then start it up again and see how it does. Also I did transfer the choke shaft and throttle shaft from the original carb over to the Homelite carb. Slid right in. As a trial run I pulled the guts out of the muffler, But left the sheet metal covering the final exit of the muffler. VERY snappy response from idle to full throttle. I need to get a chain and try it in some wood. Hopefully will have enough snort to pull a 24 inch bar with 325 chain. Also removed the fuel inlet fitting from the original carb and pressed it into the Homelite carb so the fuel line would fit easier.