Why is my 441 spitting the plug out?

[Allagash350]

Hey guys,
So I have an 8 or so year old 441 magnum with 20 inch bar. I bought it barely used from an arborist and have used it quite a bit between tree work and firewood.
Anyways I've never had a problem with it until this spring. I was cutting some pine, sharp chain, fresh gas oil, clean air filter etc. Had started right up that morning no problem.
So while I'm cutting the pine it loses power slightly but then revved back up and was fine.
Keep cutting then heard a loud pop and the motor died. I didn't feel any compression and didn't try to restart it. Just went to the dealer and figured it had blown. An hour after dropping it off (just enough timefor me to convince my wife why I needed a new 461) they call and say saws all set, plug came loose.
No real reason why, they just said it can happen with vibration etc.
I know these guys real well and do business with them regularly so we joked about it etc. No problem since then, cut quite a bit of wood this year with a lot more tree work than usual. Apples, maples, oaks birch so some hard wood but it never skipped a beat.
Until this morning I was cutting some oak and it did the same thing.
I think at this point the threads have to be stripped pretty good from the last time because it didn't just come loose it was completely out of the hole.
So should I lock Tite that thing in there or what? Why is this occurring in the first place?
I very rarely service the plug, so it's not like I'm taking it off all the time. I get a new plug every spring usually. Appreciate the help and advice!
Sorry for being long winded

 

[DodgyNomad]

Could have been undertightened, check the threads to make sure they weren't boogered up at one time and had a poor repair. I'd torque it to spec one more time and run it and see what it does. If it comes out, I'd try a drop of medium loctite and see if it stays put.

 

[Jazzberry]

I have purchased two separately damaged Stihl 026 saws that this had happened to. Both saws had the owners try to put a helicoil in to repair stripped threads and they both ruined the cylinder. Makes me check the plugs every so often.

 

[salecker]

Hi
Repair the threads with a Helicoil spark plug repair kit.
If that has already been done and has come out, then you can have the hole welded up.Then new threads cut.
I have a 046 cylinder that had a repair which wasn't done right and it came out.I installed a new Helicoil with some hardening metal putty.It lasted 1 1/2 years then it came out.Used cylinder fixed it this time.
The old cylinder will be getting welded and taped.Then it will be ready for the next one. This was a saw from a wood cutter,not mine.

 

[Allagash350]

Thank you for the responses. For those that have experienced this and repaired it, what did you do besides the helicoil?
Also any idea what would cause this?

I couldn't get the old plug back in beause the threads were kinda messed up so I put a spare in. Started right up and I did about 10 or 15 minutes on the wood pile and it was fine. Going to have to figure something out before it does more damage. Or just keep tightening it

 

[Jazzberry]

i replaced the cylinders on mine.

 

[duramaxman05]

I went through the same thing with my 441 back earlier this spring. I replaced the plug and i dont think i tightened it up enough. I was helping clean up the tornado mess at my uncles house and all of a sudden, i heard a loud poof and it died. It pulled the threads out of the cylinder. They are quite proud of new oem cylinders. So i opted for a time cert insert. I think they are much better than the regular helicoil. So far its been running great. Mine is around 10 years old also

 

[Allagash350]

I went through the same thing with my 441 back earlier this spring. I replaced the plug and i dont think i tightened it up enough. I was helping clean up the tornado mess at my uncles house and all of a sudden, i heard a loud poof and it died. It pulled the threads out of the cylinder. They are quite proud of new oem cylinders. So i opted for a time cert insert. I think they are much better than the regular helicoil. So far its been running great. Mine is around 10 years old also

Thanks for the reply. I called the shop and they had intially said they use heli coil, but after calling today learned they also use and recommend the time sert. They said they could do it for under 100 dollars so I am going to go that route as I do not have the time or the confidence that it would be as clean as they would do it.
Thank you for all the help and replies! Hope to have her up and running soon!

 

[Sean McGillicuddy]

Keep us informed please!

 

[Allagash350]

Well I picked up the saw on Tuesday, they said it was a successful operation, except that the tech who did the job only weighs about 85lbs and needed help to start the saw haha.
I haven't run it yet aside from starting it at the shop but I'm hoping this fix lasts!
For anyone who is doing it themselves and stumbles across this thread, one thing they said was that if I go to change the plug down the road to make sure the saw is cold, as the lock Tite may not hold as well if I did it warm.
Total bill was 64 bucks, including a new plug. Just in time too I've got next week off and have a ton of wood to cut and move! Thanks for all the help and replies

 

[Allagash350]

Well I got to put some time on the saw this past week moving almost all my scrounged wood from my dad's house to mine.
Seemed to run and start fine, ran 3 tanks of fuel through it.

Buried the bar in some wet red oak rounds and it didn't miss a beat.

Thanks again for all your help and the time cert tip!

 

[WoodyIsGoody]

For anyone who is doing it themselves and stumbles across this thread, one thing they said was that if I go to change the plug down the road to make sure the saw is cold, as the lock Tite may not hold as well if I did it warm.

I always put a bit of Never-Seez on the threads of a new plug, especially important on aluminum heads. This is such an effective lubricant you need to be careful torqueing the plug. On new plugs, I go finger tight and then 1/3 turn more. On subsequent tightening of the same plug, only 1/4 turn. Never had one seize or come loose. And resist the temptation to inspect the plug unnecessarily because the compression gasket will become overly flattened eventually.

 

[Highbeam]

I totally stopped replacing spark plugs. I'll add this as another reason.