Yesterday my Sthil ms250 blew the sparkplug out. First time it happened thought that maybe it just got loosened up from bouncing around. Reinstalled plug but after about 5 mins of running it happened again so now she's out of commission for the time being . anyone have similar incidents like this?? What's a decent fix?? I was thinking maybe a helicoil??
Helicoil I think. You could also get a new cylinder, or weld the the plug in :^P I have a mower in the garage that has a stripped socket. I crossthreaded the plug when putting it in, and boogered up the threads. I inquired about having the work done, but it was more than the mower was worth. If I ever get some other need for helicoils, I may fix it. Not worth buying the gear for that.
That is the problem with helicoils or other thread inserts, the whole kit must be purchased for a one time use. Have you got a reputable saw shop nearby? It might be worth getting a quote.
If it is a machine that is "not worth fixing" otherwise, I'd probably put I a new plug with a high temp epoxy on the threads and let it cure good before use. You'll never change the plug again, but if it wasn't worth fixing you didn't have anything to lose. Otherwise I'd use a Heli-coil, I've had to use them on automotive aluminum heads before.
FWIW a "time sert" would be the best option because of the way they lock in place .As has been mentioned the kits are very costly .
You can buy a cylinder from China for $20 . Not a particularly easy replacement, but I bet you can do it if you want to.
If you have a larger Stihl dealer around they may have a junk saw with a good cylinder and just give it to you.
I see you can get a no name thread inserts on e bay for $8 to $10, no idea if they are any good.
Well after a day spent in the woods pondering/stressing over all the good/bad/what ifs and worst case scenarios that could only happen in my mind I've decided ill just take her in to the shop. I prefer to if i can repair my own equipment but when it comes to something that I'm not totally sure about (or more often then not dont have enough time) i will send it to our local Sthil shop which is an Ace lumber yard which i worked at when i was younger and had a boss who is a heck of a saw mechanic and is my go to guy when i need parts/help/advice.
An automotive machine shop may also be an alternative for having a helicoil installed (if your local Stihl shop hasn't done one before).