extremely high compression problem, MS461

[SeMoTony]

I looked at the saw again today. I narrowed it down to the timing problem. The decomp was weak, so I swapped it out with a better one from a parts saw. It still popped right away though when in run. When the switch was in off or when the spark plug wire was disconnected the saw cranked normally. This saw is stock. So how did the timing get off and how do I retard it?

IIRC timing slips when the key gives from insufficient torque on the nut holding the flywheel on to the crankshft taper. New key to realign flywheel solvent clean inner and outer taper of any slippery stuff line up key & keyway torque fly wheel nut to spec. should correct timing

 

[rupedoggy]

You need a new ignition. If it is still a warrantee item that would be good. Mike

 

[crotchclimber]

You need a new ignition. If it is still a warrantee item that would be good. Mike

Stihl does not warranty saws for commercial use. I read on here maybe I could increase the gap to retard the timing some? I'll give it a shot before pulling the flywheel and checking the key.

 

[alexcagle]

Internal advance curve problem has got to be rare.
Look at this on eBay http://www.ebay.com/itm/252793831001

 

[rupedoggy]

Internal advance curve problem has got to be rare.

No doubt, but not as rare as a factory installed flywheel that slips just enough to advance the timing, and still runs otherwise as intended. My experience has been that the taper on the crank holds fine, but if it slips it usually won't run at all. Mike

 

[Trx250r180]

Put an ms 460 or ms660 coil on it and be done .Get rid of that limited self advancing one .

 

[crotchclimber]

IIRC timing slips when the key gives from insufficient torque on the nut holding the flywheel on to the crankshft taper. New key to realign flywheel solvent clean inner and outer taper of any slippery stuff line up key & keyway torque fly wheel nut to spec. should correct timing

I was told the key is not a separate piece but is part of the flywheel. Most likely it has sheared and the timing is now off. Coworker said it has happened before. Ordered a new flywheel today. I still haven't pulled it but will check it before I pay for a new one.

 

[Trx250r180]

Should have a replaceable key

 

[rupedoggy]

Stick to information you are getting here. Someone told you wrong.

 

[alexcagle]

Put an ms 460 or ms660 coil on it and be done .Get rid of that limited self advancing one .

*
Those have a saw specific automatic advance curve ignition too.
It's not so much that they advance the timing, but more they retard it at lower RPMs.
The flame travel in the combustion chamber at high RPM needs a head start in order to achieve efficient combustion.
It's not "new" technology.
The "rev boost" Husqvarna saws utilize the quicker curve to accellerate faster.

 

[Big_Wood]

an unlimited 460/660 coil will not solve that kick from the timing. at least it didn't with mine. mine i sold before i could change it but if i decided to keep it i would have advanced the timing further. all engine will have a sweet spot where they kick like a mule. some bigger pull start engines will damn near break your wrist if they fire back at ya like that. the way i found timing is the factory is close but if you retard it's usually for a negative in performance. if you advance past the spot where they kick hard, there will be a point that it will eventually not kick as hard, and without the power loss of retarding the timing. unless your timing is currently off stock for some other reason i would try advancing the timing a bit to see if the kick lessens enough to be managable.

 

[Johnnybar]

Sounds like a piece of junk...dibs on it for $50 shipped.