STIHL 075 076 DECO THREADS STRIPPED, ANY BODY KNOW OF A REPAIR?

[alexcagle]

My decompression valve popped out somehow, and the threads are stripped. I had installed it tight with red Loctite when I built it a couple years ago. Anybody know what size and pitch the threads are on the later version, and if there is a heli- coil? I've seen some early deco's that are a bit different in the way they are designed. It wouldn't be so hard to fix except for the way it has to be centered on a seat and has to get tight before the body of the deco bottoms out on the top of the cylinder.
Any help or suggestions would be appreciated, except of course, " replace the cylinder".

 

[VK Johnson]

Although I can't help you with the thread, rather than a Helicoil, I'd suggest going with a Timesert...actually a steel threaded bushing that installs similar to a Helicoil, but in my opinion, a better product. You can probably find a local auto machine shop who is set up for those, although kits are available on line.

 

[alexcagle]

Oh yes. I agree. Timesert is da stuff. I have one of their kits to fix threads in chainsaws & cutoff saws. I love them! I've put in about 50 of them. I even install them with the cylinder still on the saw. Just hang it upside down and use axle grease There is no equal out there in my opinion.
I'll take one of these spare decos up to the hardware store and see if I can figure out the pitch.
If so, I may see if I can cut a slot from the side into the boogered up thread hole about a 1/3 the way In, and put a nut in there to fix It.
If there is room...

 

[Little Al]

Being a Stihl it will be a metric thread I'm not sure but it could be the same thread as a 10 or 12 mm spark plug. Agree with other posts Timesert or other Solid thread insert is the best way to go
plug size 10mm x 1.0 12mm x 1.25