New MS 661-c broken spark plug.

[pinkfireman]

There is room in the chamber but not around the edge of the cylinder. The flat around the circumference of the chamber has way less clearance than that electrode strap.

Thanks!

 

[av8or3]

I looked around and found a pic I took when it happened to me.

 

[pinkfireman]

I looked around and found a pic I took when it happened to me. View attachment 312757

Ouch!

 

[qurotro]

I'm too late on that one. I took the front off of the muffler and got the piston on a down stroke so I could see in the cylinder. Left the plug out and shined a light inside and never saw it, blew it out with compressed air though the plug hole. Ran it Thursday for about 2 hours and it runs fine so far, if it's still in there I don't where.

Dont worry then If you ran it 2 hours fine, not in the muffler, its not there anymore.. Just pure luck this time.. that little piece of metal will blow the engine up in like 2 minutes

 

[Moparmyway]

Dont worry then If you ran it 2 hours fine, not in the muffler, its not there anymore.. Just pure luck this time.. that little piece of metal will blow the engine up in like 2 minutes

Not nessasarrily …..
It could be in the crankcase justawaitin for a sideways cut to allow it to wreak havoc on the saw

 

[qurotro]

Not nessasarrily …..
It could be in the crankcase justawaitin for a sideways cut to allow it to wreak havoc on the saw

Hm.... thinking about that tiny bit hiding between the seal and the bearing?

 

[Creaky limb tree care]

Hm.... thinking about that tiny bit hiding between the seal and the bearing?

I think I'm going to have nightmares....

 

[av8or3]

I’ve had two occasions when I suspected internal damage (happened while I was running them) and I decided to pull the cylinder to look. Both times there was internal damage found. There was this one and the other was a piston pin bearing failure. On that one the bearing cracked and displaced a tiny piece of the cyl wall, right in the corner of a transfer port. It was hanging there like a loose tooth but I couldn’t get to budge. UNTIL I heated it up with a heat gun and it FELL OUT. I guess my point is , if you haven’t found that electrode, and you haven’t really looked, you have every reason to expect that saw to grenade. When will be up to the saw. Now , on the other hand, if you’ve looked and done all you can, whether you find it or not you should expect the saw to live and as a side benefit you have a pocketful of new knowledge about the ins and outs of a 661. My bet is you find it embedded in something.
Good luck man, I understand the nightmare thing.
It’s a great time to get to know your 661.
If you look closely at that pic of mine you’ll see the piston has been beaten all up in the squish area all around the top. That didn’t happen in just a few ignition cycles. It was hundreds maybe even thousands before it finally got caught by the piston in an exhaust port. You will find damage , just don’t know if it’s little or a lot.

 

[pinkfireman]

I think I'm going to have nightmares....

I know I am!!!!