Chainsaw Repair

Took two-yr old 235e 14" to reputable small engine dealer/shop since it wouldn't start after sitting for a year or more.  Unfortunately, it last had Ethanol based fuel which ate up the purge ball and rubber fuel lines...... All that was replaced last a few months ago at another reputable shop, and I was advised to consider True Fuel (non ethanol-based) supplied as a pre-mixed product in a can at Home Depot.  I bought a can, put it in the chain saw, started the machine with no problem, let it run for a few minutes, then shut it down.  Next day as I prepared to do some minor limb trimming, the darn thing would not start, and has not started on multiple occasions since then.

Since the repair shop warrants his work for only 30 days, I'm SOL as regards going back for a free look.  So, I wonder what I might do on my own to sniff out what possibly could be wrong.  I'm handy with electro-mechanical things, so am willing to attempt any reasonable suggestion.  I actually have considered injecting carb cleaner or ether into the intake manifold, but I can't determine where that might be (short of removing all the covers.

Any suggestions would be appreciated.  Thanks.

Check for spark

look at plug after trying to start it? -Is the plug wet with fuel?

How does the compression feel? Hard to spin over?

Pull the muffler and look at the skirt of the piston through the exhaust port?

I truly appreciate the responses to my dilemma.  Thank you. 

The True Fuel is in the RED can (50:1) pre-mix......... which is working great in one other Husqvarna I own.

As for the diagnostic tips, thanks for the reminder of the 4 key ingredients.  Later today I plan to test for spark, and will look for signs of fuel  on the spark plug when I take it out.  Something in the back of my mind makes me suspicious of the kill switch/lever.  If no spark, that is the first place I plan to look, thinking maybe the contacts are shorted or somehow grounded.  The engine seems to have strong compression, at least from what I sense when I pull the cord.  But I'll keep that piston ring suspicion on hand as a last resort.

Again, thanks for the feedback.  I'll return with comments after my next diagnostic effort.

Looks like the culprit is no spark.  With spark plug out of the head but laying on the head to supply a ground when I pull the cord, I see no spark in the plug gap.  I next  disconnected the yellow wire from the ignition module to the kill switch, still no spark.  I metered from the yellow wire terminal on the ignition module (with yellow wire disconnected) that appears to be grounded (unless my meter is confusing me, as if there is a very high resistance at that point). 

Not to be totally mislead, I did verify fuel is getting into the cylinder head, and there appears to be good compression.  I visually checked the carb. intake but see no reason for air starvation.

I have another (new) 235e, so just for grins I think I'll substitute its sparkplug into the failing machine, although the sparkplug in the failing unit has less than 3 minutes of run time on it.

Unless someone has a suggestion which I've not tried, I suppose I could search for the best source for a ignition module and trust that for whatever that costs ($30 or less), that has a high probability of fixing my problem.  Am I ok with that thinking?  Thanks in advance for your thoughts.