Small Engines (Lawn Mowers, etc.): Weedwackers galore...none work, craftsman weedwacker, craftsman weedwackers

Question
This is driving me nuts!!!  I bought a craftsman weedwacker two years ago and used it great first season and out of the blue on the second season it quit mid usage. Every time i have tried to get it started, it might idle and then quit unless I choke it (Model358.795580).  Thats ok because I swuitched to my Lawn Boy (older) and used it until it did the same thing.  I have two other old craftsman weedwackers as I enjoy fixing things and keeping older things running and am very proficient at it.  I have changed the plugs, checked the gap, saoked and cleaned thoruoghly both carburators, verified good spark, (mufflers are unable to be taken apart to check buildup), insopected cylinders and pistons, replaced the in tank filters, and the bulbs to pump fuel, inspected the needles which seem fine, diaphrams are fine, air intake seems good and clear....I shouold say that the old craftsman I am not conscerned with, I can just toss them, but the two year old craftsman had got me livid that I spend my money on something that just quits so soon with no apparent explanation.  they (new craftsmen and lawn boy)run if I choke them so isit just an adjustment there.  They also both drip of excess gas/oil mix when I am doing this.  Would love a second opinion here.

Thanks,
Ryan

Answer
 Hello Ryan:

 Try Running the Engine without the Muffler. If the Muffler or the Spark Arrestor Screen becomes Clogged, the Carburator cant Draw enough Gas to Run Properly. You May need to Replace the Muffler. The Excess Fuel Mixture Leaking Out of the Exhaust is a Sign of a Clogged Muffler or Exhaust Port. Oil Leaking out of the Muffler is a Sign of the Oil to Gas Ratio is to High. I use 32:1 Oil Ratio on All my 2-cycle Equipment and have Very Little Oil from the Muffler. The Air Mixture is Set with Both the H and L Air Mixture Screws Turned Out 1 1/2 Turns from Seat. Hold Throttle Full Open and Start Engine. With Throttle Full Open Adjust H Air Mixture Screw Until the Engine Revs Properly. Adjust the L Air Mixture Screw so there is No Hesitation when Going from Idle to Full Throttle. Then Set the Idle if Required. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John