you guys are great.
here’s where I’m at:
did the oil change-BLACK- cleaned as best i could w/out removing carb… thats a longer project then i had time for… or honestly trust myself with.
there is no adjsutment as burntime said-- thesemowers are like throw away items.

- i start it up, perfect on first pull as always- runs great for 2 minutes then gets to reving up and down… high and low a lot.
i remove the plug- black again. there is soooo much carbon built up inside that hole its amazing.
i think that is my problem- just so much dirt/carbon on the head.
this mower is only a year old :(

can i use this seafoam or an auto injector cleaner for that? 
I really run it just on seafoam- no gas?

Seafoam will clean the entire engine.  You need to mix it with gas.  If you really want to go crazy dump some seafoam down the carb until it chokes out.  Let it sit overnight, add gas and seafoam and start mowing.  My neighbor had a snowblower that was sitting for 3 years with old gas.  I drained it all, drained the carb (you would have to run it dry) and added gas and seafoam.  Ran it for 10 minutes in the drive and shut it off, did this 3 times on a saturday.  Sunday came and started it up and it ran great.  Check the can, I think seafoam is also form of stabil!!!

If its really bad you may need to pull the head to remove the carbon.  Sounds like it is running really rich?  I forgot, did you say you checked the air cleaner?  If it is full of crud it will limit air and you will get a really rich mixture.

ah, ya know, i mentioned that it (the air filter) is always clogged.. constantly cleaning clumps of dirt.
it is clean now, but that would cause it to run rich as you said and black buld up.
and man, if i pull the head, i’m gonig to break something that wasnt broken. its jsut me.
picking up the seafoam at pepboys at lunch. hope that helps.

Absolutely it would run rich with a dirty air cleaner.  It custs the air supply just like choking it.  Seafoam is 5 bucks and you are only gonna use like a quarter or eighth of a can...cheap fix if it does the trick!

ha, i just picked it up at ~7.00
ah oils @ 121. a barrel so much for 5. bucks.
whatever.

but it will probably be worth it.
gonna try tonight.

Does that mower have a self adjusting carbertor? your do you have to choke it?

there is the dopey prime button, push lever forward, pull cord mow.
and the carb runs off the spring lever.
i cant find anything anywhere to adjust.
i chk the manual 3 times. nothing

think burntime is right, they are set, there are no real adjustments.... like a thowaway mower.
as i said its kind of sad for a Craftsman/Briggs mower.
quality isnt too bad, but designed poor.. like by people who have never had to mow a lawn.
-the sparkplug is up front, so when you mow up/under a bush it touches and shorts unless you back up fast.
-that carb spring is above left of the plug, gets snagged on things, and crudded up.

YA KNOW now that I think about it, the air filter is up front too, above the spring, the dirtiest part of the mower. if rotated to the back of the mower, it would really eat less dirt.
IF they rotated this engine around (the way i remeber all my mowers as a kid) it would be a much better mower.

and damn while I’m at it..... I hate these “auto shut off when you let go” levers on all the mowers. i velcro it down when i mow, but then i lose the damn velcro.

thanks guys

I have a Tecumseh with the same type of carbertor on it I always empty the fuel for winter shut down but there isnt an adjustment. I think you are on the right track with sea foam.

I too have an aversion to non adjustable plasticky stuff, but have had good luck with this modern Briggs carb.  I had an old mower that I could never get to run right and then I put on a used one of these non adjustable plastic carbs, and the engine has run great ever since.

I think you could have either a loose air inlet elbow or a bit of dirt still in the carb idle emulsion passage.  What this does is starve the engine for fuel, triggering the choke to come on and enrich the mixture.  This speeds up the engine, then the choke automatically comes off, and the engine powers out again and drops speed till it triggers the automatic choke and the cycle repeats.  Thus the large amount of soot produced.

Try taking the carb off and cleaning it in gas, then try to peer through the tiny passages with a light source behind to see if they’re clear.  There should be one big one (maybe .03 or so) and one small one (perhaps .01).  Use a strand of wire from small multistrand copper wire to poke the holes clear.  For super tiny holes I have used an old accupuncture needle, they’re amazingly small.  Yes-accupuncture can cure lawnmowers!

If you have access to an ultrasonic cleaner then put the carb in a detergent solution in it, after preliminary cleaning in a little solvent or gasoline.  These machines do an excellent job.