The screw on the bottom of the bowl is the main jet. From a light bottom-out of the screw, back it out 1 1/2 turns. It should run smoothly. Tweak it for smooth operation.

The other screw is backed out 1 turn, to start. Reduce the engine to idle. It should idle smoothly. If not, adjust the horizontal screw in or out.

Raise the throttle suddenly from idle to high speed. If there is any bogging, turn the horizontal screw (idle screw) in or out so that when suddenly going from idle to high speed, there is no bogging or stumbling.

Once this is fine tuned, put the engine back up to high speed and tweak the main jet for smooth operation. You should now be set.

If operation isn't satisfactory, your bowl nut (main jet) may have varnish and need to be cleaned. Follow these directions:

From time to time the question is asked about why an engine will not run long, or smoothly, or will start with starting fluid and not continue to run. The problem is usually because of a blocked or constricted jet. The small ones are easy to miss.
Shown are 3 of the typical jets and the small holes. All 3 are Tecumseh jets. Briggs jets are similar with the center-bottom hole and one on the side. All these holes need to be fully clean and open for the engine to run correctly.
Some jets only have the center-bottom hole.

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If you need to overhaul the carb, see this link:

http://forums2.gardenweb.com/forums/load/lmower/msg061726346162.html

Great info baymee & ewalk - THANKS! This carb has the main jet like the one pictured above with the red arrow. I had cleaned this jet but never realized that tiny hole the arrow is pointing to. I ran to the mower shop this morning to get a replacement needle and seat and was told that I could not buy these seperately, so I was sold the full kit. This will be the first time I have removed/installed welch plugs. It seems pretty straight-forward. Your pictorial instructions are great for the first-timer like me. I appreciate that more than you can imagine! I got more from your instructions/pictures than I did from watching an hour of youtube videos last night. Thanks Again!

Tecumseh specifically makes a needle, seat, and bowl gasket as a kit. I guess your dealer wanted a bigger sale. Have fun with the project.

My distributor hasn't had the oem n&s kits for some time. They had been upgraded to come with the bowl seals- which was nice. Now its OEP Krap and a Briggs seat so it doesn't leak....

Well it took me about 30 minutes. The most difficult part was removing the smaller welch plug. It seemed thicker than the larger plug and took me a while to carefully cut thru it. I cleaned all the holes with the soft wire, then blew carb cleaner thru, then compressed air. The generator started right up. I gave the main jet 1/8th turns until the engine ran smoothest. Still not perfect. It will run smooth for 15 secs, then a small sputter, then another 15 secs smooth. I tried playing with the idle speed adjustment, but it had no effect. Not even sure why the idle screw exists as there is no throttle control at all on this generator. Anyway, thanks to all for the details. For helping him get this running, my neighbor gave me his old 1200 watt generator. If nothing else I can use this to keep my sump pump running when the power goes out. I have some questions about this machine that I will post in a new thread.

You might want to do the "final tweek" to the MJ when the engine is under heavy load. That's where it's important.

Follow Bill's final tuning adjustment suggestion on unit has settled down . You may wish to run some fuel conditioner through the system to ensure all residue has been removed . Normally a 1/4 tank runs the course for final circuit purging. Congrats on the repair and replacement ordeal , you are reaping the fruits of your labour ..Good job !

The idle adjustment screw adjustment will also have an effect on the main power circuit. That is if all is working as it should. IE air leaks due to a worn throttle shaft, gasket etc. Or possibly not fully clean.