please help me figure out what to do with my ms660.
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Chainsaw Jim
CJ Saws, LLC
It sounds like a crankcase seal is chowdered and the spring is giving the transfers and sides of the piston pure hell. Probably chunks of plastic bearing cage too based on the mentioning of the clogged screen in the muffler.
srcreen in the muffler was clean. screen behind the air filter was clogged. Thanks
spark plug came loose one time, The cylinder thread looks perfect. threads on the little nipple (on top of the plug) got wasted after they got loose and vibration got to them.
Is it a big job to dig inside the cylinder? I know on some saws, you literally have to take the saw completely apart
Chainsaw Jim
CJ Saws, LLC
Is that spark plug a resistor type? Most non resistor plugs have a threaded tip. You may have the wrong type of plug.
Not really sure what you mean by "resistor type". I was talking about the nipple or the tip that the wire hooks onto. Got the saw brand new with this plug at one dealer. Couple months back was at a different stihl dealer and picked up a spare plug for it, brought it home and compared it to make sure I got the right one, sure enough it had the same number on it
For a start I'd just visually inspect the top of the piston through the spark plug hole with the piston at TDC, or get a video bore scope & have a look at BDC.
Thansk
Chainsaw Jim
CJ Saws, LLC
It's simple. All you'll need is the T-handle Stihl t-27 torx tool and a small but long flathead screwdriver. Remove the muffler, then remove the four bolts to remove the top handlebar, then the top cover. There is no need to remove the rear tank/handle or carburetor. It'll now be a good time to loosen the four cylinder bolts which is what you need the special Stihl torx tool for. After that you should be able to reach the intake boot clamp with the flathead to loosen it enough for it to slip off as you lift the cylinder from the base.
It's always a good idea to use an air hose nozzle or something to pick the sawdust gunk clean around the cylinder base before loosening the bolts.
those are over $100, should I rent one?
find a mechanical workshop with one & slip them a few $ for their trouble.
thansk
Update. I purchased a t-27 off ebay, will provide pictures when I take it apart. I am hoping I can take a very fine sand paper and polish the piston and maybe the bore and throw it back in. Is that a good idea?
Chainsaw Jim
CJ Saws, LLC
No it isn't if too much material needs removed. New oem pistons are only like $55. It's the cost of a whole cylinder kit that kills you.
I try to buy 92 ethanol free , but sometimes get the 87 because that one is closer to home. Ethanol free tho either way.
