My IH Cub 184 tractor has a problem that sounds to me like its running too lean all this year regardless of what I have tried to do to fix it. It will run pretty good with the choke part way on is why I'm saying running lean and there is no smoke when I do it. I've done the stuff that I know causes that - cleaned the carb and looked for leaks. I thought I had found a leak in the manifold gasket and changed it but didn't fix anything. Concerning the carb I have had it off several times and was able to get a wire through and spray carb cleaner through every passage. Carb looked good first time I took it off. Its a Zenith carb. I have a good flow of gas to it. Float level is set per I&T manual - can't remember exact number. Valve clearance is set by the I&T manual and I rechecked it to be sure. I just had some oil on the breaker points and cleaned them so I know they are good for now. I hope someone has some other ideas as I am out of ideas.