Wont start!

[kaplangmk]

Don't know the model of the engine on my Craftsman chainsaw but I don't think that matters.
It was running perfect;y the last time I used it but just stopped and now won't start.
Rebuilt the diaphragm carb and that didn't help.
It has compression and a good spark to the spark plug.
Fuel and oil mixture is correct.
Replaced the spark plug but that didn't help.
Tried spraying starting fluid through the carburetor and not even a pop.

I have many years experience with 2 strokes including Clinton, West Bend and McCullough. There basic engines that if they have compression, good reeds and getting fuel and a good spark will usually run but this one has me stumped.

Any help here will be greatly appreciated because I want to put the saw back to work
.Thanks

 

[Bob Hedgecutter]

Well, its not getting something it wants.
Is the electrode of the plug getting wet- confirming fuel is actually getting through the carb and into the combustion chamber?
Has the muffler been removed to check piston for scoring?
Timing- if the flywheel has moved position it could be sparking at the incorrect time and never start.
Lack of impulse.
Screw too tight (threaded in to tube not pushed) in tank vent.
Massive air leak from bad main crank seal/seals- or any other entry point to the cylinder.

Starter fluid is not great for 2 strokes- washes off the oil film. Simple dribble of mixed fuel through the carb throat will confirm or deny.

 

[kaplangmk]

Plug isn’t getting wet. That’s why I tried some starting fluid. If the ignition timing is ok it should have at least popped. I do know the issue with not having oil with the fluid but I needed to try something.
I’m going to check the aluminum key for the fly wheel. Maybe it split and the timing is off.

 

[kaplangmk]

It was the aluminum woodruff key. It split and the flywheel shifted causing the ignition timing to be off. Replaced the key and now it starts right up,
As Roseann Roseannadana would say
“it’s always something!”
Thanks for the help

 

[Bob Hedgecutter]

Good to see you got it sorted easily- next step was going to be pressure and vacuum test and if you do not have the gear to do that.....