Something weird happened to my saw...any ideas?

I was running my 361 Saturday and it was right about 20ish degrees. I had the intake thingy in the "winter" position.

After running it hard bucking up some hickory and beech logs 18"+ for about 20 minutes it started to lean out. I thought I was running out of gas, and it was almost empty, but not quite...I filled it up and resumed cutting. It promptly leaned out again and then just quit...from max RPM to dead just like that. Oh chit...it just seized. That's not good.

I pull the rope...and it don't pull. After a few minutes of running through a top end rebuild in my mind and enough %$#$%^#$ words to make a sailor blush I picked the saw back up. Pulled the rope...still no go. I usually don't use the decomp valve but I pressed it, pulled the rope and it felt relatively normal...and it started right back up again and ran like a champ for the rest of the day (until my dawg fell off and I couldn't get any leverage on those slick bark beech logs).

Hoping one of you chainsaw whisperers might have a clue as to what happened. I'm completely stumped. Did my carb ice up? Some sort of vapor lock? Should I pull the muffler and have a look? The last time I pulled the muffler (probably 4-5 tanks ago) it looked really good.

 

I'd pull the muffler cover and look inside.. If your carb did ice up, maybe a piece of ice got into the cylinder and took up the squish band area, then melted and your saw pulled over again.. odd that it ran the rest of the day fine,,, maybe it had warmed up enough that the air density changed as to not cause icing the rest of the day.. I have the same saw, MS 360,, has to be all of 12 years old,, I took the warm air screen right out of the cover and have never had issues cutting in the cold.. Saw still has all the original carb parts, fuel lines and fuel filter.. Only have changed the plug once and air filter... Amazing, over 120 cords cut... Of course chains, sprockets and bars wear... That's been one amazing saw for me... Amsoil sabre, Sea Foam , and premium fuel.. all those years and no problems.. It could have heat seized from leaning out and then cooled and broke free... A stuck ring will force the piston to one side and cause a seizure as well ... Check for a lot of carbon build up...

 

Check the piston. The cooler temperatures could have caused it to lean out.

 

I'll pull the muffler tonight and have a look. Wish me luck.

 

Heading out to the shop after I get the young'uns to bed.

 

From another thread about Leatherman's

Perhaps it is bad karma -- but if you had just brought a leatherman with you could have torn down and fixed the saw on site

Good luck.

 

I guess it is bad karma. Piston is junk.

 

Dang it

 

Well that sucks. Sorry to hear that. Hopefully you can save the cylinder.

 

Bummer

 

That sucks! Sorry to hear that....... Wonder what was causing it to lean out and is that what toasted the piston? Was it scored?

 

Jug is lightly scored. This is my first rodeo so I'm not sure what to do.

 

Before you buy a piston and either fix or replace the jug,put it back together and do a pressure/ vac test to be sure the seals aren't leaking . Also check your impulse and fuel lines. Determine the cause before you rebuild it .
361 s are nice saws And worth putting the money into .

 

Agreed . That would be an even worse day if you rebuilt it...and scorched the piston 10 minutes later . Check it all out...and start fresh !

 

Oh man

Known good fresh fuel/ strong side of oil in the mix ?
Clean air filter?
Have a muffler screen, is it clean ?

 

I have no idea what happened. It ran fine up until about 3o seconds before it puked. Good thing I have 20 cord on hand because I have 0 time to work on this right now.

MM, PM sent.