Sheared flywheel key?

I wonder if that'd create any of your cylinder carbon marks or streaking... not sure though.
How's your plug look?
I've heard coils are rare to go (wish I could say the same about Cub Cadet riders... arrrr), but they do go on occasion.

 

I may have misread or not read but hard pulling would be advanced timing. The key being sheared would goober the timing and make it easy to pull. ???????

 

Not much of a Stihl guy but some of their flywheels have two keyways marked A and B. can't see in the pic but does the FW have two keyways? If it has two, you have to use the correct one for the saw, otherwise you end up with what you are fighting with.

 

Single keyway, I read about the A & B.

Keep in mind I've never touched the flywheel, and my BIL sure as hell didn't. It previously cut a good 4 cords for me in +/-8 tanks. It was a strong runner when it left my hands.

When I have a free evening at home I am going to start digging in.

 

Good luck with it, I hate working on Stihls but I do it! Too many variations of everything! Makes an old man's head spin!

 

I had a wife free evening, so got back to this saw. Cleaned everything up with scotch brite.



Squish was .023" on average with the gasket delete.



It's all back together minus the bar. Letting the gasket set up and hopefully fire it up Saturday sometime just to see. Will perform a vac/ pressure test when I get the proper tools to do so.

I did notice the exhaust was real carbon'd up, like creosote looking, and the gasket between muff and cylinder showed oozing. I cleaned it all up.

Could a lack of back pressure cause the timing-esque symptoms I described previously?

 

I am hopefully putting this thing to bed.

The saw is back to running. Hopefully I will cut and tune tomorrow.

This is kind of embarrassing, and I am still not sure if it is cured, but I found the L needle way backed out. I reset to 1 turn out and the saw ran off choke and ran great.

I rushed to suspect flywheel based on how I got it back. Now I wonder if my brother in law mucked with the carb settings after most likely flooding it.

The saw passed vacuum and pressure test post gasket delete. That makes me feel a bit better.

I plan to keep this as my backup 72cc saw unless I can sell it to someone I know. Given I am far from 100% on its realibility, I want to be able to keep an eye on it.