260 help needed

[Bluehill logger]

So I put the used 260 i just got my bench figured I would take off the muffler to check and see how the piston and cylinder looked before starting it up. But I discovered that for some reason the saw won't turn over completely. :bang: I had the plug and muffler removed but the saw won't turn over past the top of the piston stroke, but It moves just fine until the top of the piston stroke. I can't figure this out. Piston and cylinder both look good with no scoring and both rings look to be intact. The compression release seems to be stuck but I don't know if this would be causing the problem. What could be causing this?

thanks
Rodger

 

[Dan Forsh]

Sounds like the simplest place to start would be to take out the decompression valve and see if you still can't get it to go through a full revolution.

 

[cuttinscott]

stopping at TDC is either carbon build up or the ignition coil hitting the flywheel.

Scott

 

[lostone]

Have you looked at the top of the piston, are there any small round marks the size of say a BB in the top of the piston? If so do a search on decomp release, It has been awhile but I read on here about someone that had the decomp stuck on, his had small steel ball bearings in the decomp (sorry not good at explaining) and they had dropped down into the cylinder where they then ended up smashed into the top of the cylinder, which did the same thing you are having and stopped the piston from going over TDC.

 

[rupedoggy]

If you are turning it by hand the starter dogs will stop the saw if you turn it backwards.

 

[Bluehill logger]

from what I can see through the spark plug hole the top of the piston looks pretty good minus some carbon build-up. I hadn't thought about the coil hitting the flywheel. I'll try and reset the coil gap hopefully its that simple.

 

[cuttinscott]

the coil and flywheel should not be a issue unless somebody has messed with it. You said you saw carbon that would be where I would start.
Scott

 

[Bluehill logger]

turns out the problem was carbon build-up. There was a chunk of carbon sitting right at the top of the cylinder. As soon as I yanked the cylinder it fell right out and the saw turned over just fine.
Now that I've got the cylinder off I wonder what torque specs I should use when putting the cylinder bolts back in? Also, who sells torx bits that would fit into a torque wrench that are long enough to reach the cylinder bolts? Because all I've got right now it the standard stihl torx bit.

thanks for the help

 

[cuttinscott]

I have the T-27 Torx in 1/4 screwdriver drive available for sale I use one on my cordless impact

Scott

 

[Freakingstang]

I always use a T handle and get them pretty snug. I haven't had any problems or air leaks yet.

 

[Bluehill logger]

cuttinscott

I sent you a pm

 

[Lakeside53]

Now that I've got the cylinder off I wonder what torque specs I should use when putting the cylinder bolts back in? Also, who sells torx bits that would fit into a torque wrench that are long enough to reach the cylinder bolts? Because all I've got right now it the standard stihl torx bit.

thanks for the help

10.5 MN or 7.7ft lbs.