I'm making some general assumptions here, first off the carb resembles this one:
It won't be exact because this is a 7 HP Tecumseh. Don't worry about that. Do care about whether the one you have is a float type carb with 2 adjustable jets, because that's what I'm referencing. If yours isn't then disregard this.
There are 2 jets on it, one on the left side as facing it, just above the bowl. One on the bottom of the bowl. The side is the low/midrange jet while the bowl bottom one is the high speed.
Starting adjustment is 1 full turn on the low/midrange and 1 1/2 turns on the high speed.
Heat box off, start the engine and get choke off as soon as you can. I usually start with the high speed. Adjust the high jet till it starts smoothing out. Keep going through the point it's smooth till it starts going rough again. split the difference and try it there, make any final adjustments to keep it running smooth. Might have to do a partial adjustment with the choke on, get it close then turn the choke off and adjust further.
Throttle back to about 1/2 and do the same with the low/midrange jet.
Once you have it all adjusted, gofrom low to high rpm's and back down and see if it's smooth or not. If not, adjust some more.
When you're done, put the heater box back on.
There is a Tecumseh engine manual online somewhere but I don't have the name. If you have another carb, the manual should cover it.