Outdoor Power Equipment and Small Engines - Poulan Weed Eater WT3100 won't start

Mt trusty 3 year old wead eater will no longer start. Every 10th pull or so it will try to kick, but then dies. I have already done the
following:
Changed the spark plug ( properly gapped)
Changed the fuel filter
Changed the air filter
checked the lines ( no kinks or leaks)
tried a teaspoonful of gas directly to the carburetor
Ruled out engine flooding
Adjusted the Idle Speed Screw

Any suggestions are appreciated.
Thanks,
Dave

It needs new fuel lines, if it's Poulan and it's 3 yrs old it needs new fuel lines, if you haven't checked as yet you will probably find the fuel filter in the tank is no longer attached to the fuel line. Have a good one. Geo

Check to see if the plug is firing when you pull the starter rope. If it is , then it is a gas problem.

Thanks,
As noted, changed the fuel filter- also blew out the fuel lines, seemed open, but will replace. Getting good spark.

You may have either solved the problem or junked the trimmer by now, but if not...

Take the muffler off and crank it again. If it runs, clean the muffler and reassemble. A friend's Homelite trimmer gave me fits for 2 days a few years ago before I tried this. If the muffler is clogged it will fire for one cycle, but the cylinder will be clogged with exhaust and it will never fire again until all the exhaust diffuses out maybe thirty seconds later. Then it will fire one more time, and the cycle will repeat until your arm gets tired.

Would like to follow up on Sammy's suggestion of
removing and cleaning muffler. My case is similar to one Sammy responded to. I removed muffler guard but am
not clear as to how to remove the muffler itself. If springs disengaged can they be reengaged on assembly?
John

If it's held on by springs, take them off to get the muffler off. It will take some effort to get the springs back on, but they'll go.