If it is a 2-cycle with a plastic carb, it has an idle jet.
The V-series (4.5 hp, 2 cycle) sometimes referred to as Silver Series has a plastic carb and does not have a separate idle jet. The DuraForce series (6.5 hp, 2-cycle) Does indeed have a plastic carb with a separate idle jet. In any case, your fault is I'm 99% sure, a semi-clogged main jet, which on all Lawnboy carbs, metal or plastic, under the screen in the float chamber in the middle of the carb. You remove the screen (carefully, so you can reuse), unscrew the brass jet from the plastic or metal carb body and clean it thoroughly, it has several small holes that all need to be clear. If for some reason your carb is missing the screen, you need to order one and replace it, otherwise it won't be long before your carb is clogged again.