Ok, I'm not admitting defeat on this one, but i am calling in reinforcements.
My father dropped off a Husqvarna 223l string trimmer at my house and asked me to fix it.  He owns a landscaping business, has zero patience for messing with this kinda stuff and breaks things ALL the time; so this is a common occurrence.  Usually i get around to looking at them in the evening, call him with w/e part is needed and next time he's at John Deere or Stihl vendor, he picks it up.
So fastforward to this 223L.  He drops it off, says it has problems, won't start anymore, doesn't have that many hours on it, even when it did run, it ran crappily.
I figure it's something screwy with the carb.  Jets are all working as they should be, diaphragm isn't damaged, butterflies are moving as they should be.  So then i go about a number of other things that i'll list below to save time.
New Spark plug adjusted to factory recommended gap (tested against the motor and it does fire when pulled)



Cleaned airfilter and intake box



Strong compression



No blockage in the exhaust
I've tried it with no airbox or exhaust on it and still nothing.  By nothing, i mean not even a sputter of it firing.

 





::UPDATE::



Alright, so i finally bought a compression test kit and it's 60psi, so the thing is boned.  Now i wanna know, what the hell causes this? My initial thought is bad seals, but it's only around a year old.  So impart some wisdom on, what causes these things to nose dive like this?

it got a kill switch?

as i read over what i just posted i had a thought, i have no idea how long this edger has just been sitting... wonder if i've torn the whole thing apart twice when all it needed was some fresh gas?  I doubt it...

PERR Small Engine Technical Forums - The ARFCOM of small engines!

it does, i've disassembled the handle and followed the wire from the switch to the flywheel where it grounds.  No breaks in the shielding on the wire and the wiring harnesses are all tight.

 

Found it

Does the air filter bathe in oil?
Spray some ether in it and see if it fires?
Gas shut off valve somewhere along the fuel line?
Gas cap have a vent or need one?
Fresh gas?

Manual recommends oiling for "dusty" areas.  I've letting it run open in the garage while i work on it.

I've sprayed starter fluid directly into the cylinder and nothing

No gas shut off valve

Gas cap is vented and working properly

Fresh gas is the only thing i thought of after my OP that i haven't yet tried.

 

I didn't buy it, i'm just supposed to fix it.  I've got three stihls of his sitting in the garage ready for him to pick them up.  None of them had engine problems, but the problems they DID have were more costly than a tune up.

 

Pressure test the fuel lines, and crankcase.

If it has spark, then it must not be getting any fuel. Have you tried to purge it? I have two Husky string trimmers and both of them need purging/priming to get them started when hot or cold. Try fresh mix in the tank and purge the carb several times (10-20 times) before pulling the starter cord. I believe that model has the "Smart Start" engine so you don't have to pull the cord all of the way out to start. It's kind of funky to get used to if you have been using the conventional method. The kill switch is a momentary switch so it will spring back to run after you kill the engine.

so you're spraying starting fluid down in the intake and it has good spark and good compression but still won't even sputter for you?

Ok, so you understand my confusion.  I don't consider myself super savvy on small engine, but dammit i know that spark+starter fluid = at least a sputter

 

honestly that still spells out spark problems to me.  either the lead is grounding off when you install it or something else is amiss.  

i'm wondering about your intake valve too, or sludge blocking the passageway into the chamber (i am talking 2-stroke here).

Sounds like weak spark.
What color is the spark ?
If not a good blue spark, is is probably not firing under compression.

Might be a bad magneto.  Check the gap, do a resistance test.

About 10 years ago, a neighbor gave me his old Husqvarna 22R trimmer that wouldn't start. He said it was a good weedeater for the last 14 years but figured it was time to bury it. I put a new line feed on it and dumped the old fuel and replaced with new and it ran like a champ for years. In the last couple of years I have had to tinker a little to keep her running. That includes holding a few pieces together with JB Weld, zip ties and superglue...but she still runs like a top at 24 years old. When I have had issues of not running, it was bad fuel (twice) a split diaphragm, a clogged fuel line, and a clogged jet. I'm saying bad gas or a clogged line...or maybe you are sucking air in through someplace it's not meant to...my briggs and stratton is prone to shearing gaskets on the intake that messes up the fuel/air ratio and keeps her from cranking but that's a two dollar and 5 minute fix..



roy d...yup 24 years old and still running strong

Pin holes in fuel line? Sheared key allowing trigger to move?

Now this is a small engine.

smallest v8 engine

If you're not even getting a pop with ether, I'm with the guys saying I think it's still a spark issue.

Check for spark. Check compression.

Compression below 110= Fried.
No spark= disconnect ignition switch and leave open and try again. if still no spark check plug wire/coil connection...still no spark= shit coil.
The ignition switch and associated wires are notorious for getting FUBARED from vibration, and mung.

Use 50-1 premix in a spritz bottle and spray into carb...not ether. 2 strokes need the oil and can be damaged from running on either mometarily...even if they will tolerate it a couple seconds at a time.

Good luck!

Ok, thread resurrection.  I finally went out and bought a compression test kit (i needed one anyway for the bike i'm trying to rebuild).  Compression is 60psi, so out of curiosity, what causes this? My initial thought is bad seals, but this trimmer is only a year or so old.  I'm still hungry for small engine knowledge, so what would lead to such a drastic loss of compression?

 

Repeated attempts at turning over with just starter fluid in the cylinder.



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Well there had to be something before that, and all other systems are functional.  I swapped the carb, filter, and fuel tank to a known working unit and it fired up fine.  I know that engines lose compression a hell of a lot more ways than just having starter fluid sprayed in them.

 

I would bet it got run on straight gas.

60 psi is pretty good for a two stroke, 110 psi would probably just about rip your arm ot of socket if you tried to pull start (ask me how I know).

I would imagine it has junk fuel. Take the tank and fill it with PURE gasoline NO OIL then remove spark plug and pull chord a number of times (enough to work fuel into carb) then empty carb and tank and fill with mix fuel and see if you have any luck. These problems are almost always fuel. If your not getting good spark the coil or the magnet on the flywheel is likely the problem. You can check the gap on the armature (iron plates that ride above the flywheel) and if flywheel is rusty you can clean around the magnet with some steel wool.

The last two I took apart had the rings stuck in the lands of the piston. Excessive carbon buildup from different oils being mixed together and low grade/stale gasoline.

New piston and ring set did the trick for around $40 in parts.

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