If it is a true bog, that is a lean condition. If it stumbles, stutters, or loads up, that is most likely a rich condition.
I would suggest moving the clip on the needle to a lower position. This will raise the needle in the main jet, allowing more fuel. If it gets better, you have a lean condition. If it gets worse, you have a rich condition.
If the right side crank seal is leaking, you will be blowing a fair bit of blue smoke. If the left side seal is leaking, it will be sucking air in to make it leaner. To test that, you can take off the left side cover and spray WD40 behind the flywheel while it is running to see if changes. If it changes, you have a left side leak. You can also spray WD40 around the reed housing and front side of the carb to make sure there are no leaks there.