If you wind the high speed needle in all the way and it doesn't lean out/start to die, you have an over fueling issue. Being that you cannot get the main nozzle out is an alarm bell for me, it has little holes in the sides to emulsify the fuel that goes through, if they are blocked it won't run right. in saying that it should still lean out when you wind the needle in. Check that you have the right needle in it. There are two types, one is a solid needle with a viton rubber seat (green) and there is a neoprene needle with a solid metal seat. they won't work the wrong way around.
Reading you're comments to me it sounds like you have only picked up the flooding issue since changing the needle, and I personally would say you're original problem is likely to be a blocked up carburetor. Getting the stuck tube out is not impossible, I usually put the whole thing in a vise upside down, gently heat the alloy around the tube with a small blow torch and soak the inside with wd-40 or lanolin spray. I find the best then is with a really good fitting screwdriver gently work it undone, with heat it will come. just don't strip it! there is a tool to remove stripped ones. I have done it a couple of times, finding someone in a mower shop these days will be pretty difficult.
I am yet to use a china carb, have one here for an engine but ran into other problems. If you have play in the throttle shaft it is definitely the way to go, otherwise I don't think they are ever quite as good as genuine. I have heard of a fair bit of success with them though.
Last edited by nath; 13/09/20 09:38 AM.
