Here is a trick for you but you need to remove the cowl, once you have the low end right, its rare that you need to readjust it in any given season unless something else goes wrong.

While the engine is running at an idle, remove the fuel line from the carb or pinch it until the engine quits but listen to the rpms. If the engine rpm increases as the engine quits, your low end is too rich. If the rpms just go down, too lean. I set mine for a very slight increase. The dialin your high end as necessary