Are you really sure these Mod 10T502 Type 0416 H1 as I can't an IPL that this type number with in the 10T502 model.

Now if it has the 795477 carburetor. Some these has a metal jet installed in the nozzle that comes loose and gets lost which would produce an extremely rich condition. Don't have a picture of this metal jet version. Also that nozzle is can be removed and there is a small o-ring under it. This is not available separately so a whole carburetor is the only to fix this if this is the problem.
[Linked Image from jackssmallengines.com]