Stihl 4 Mix, I want to de carbonize, Need help with when to pour it in the cylinder Valve/Piston position.

[JOE.G]

Everything I read about the Decarbonizer said it worked well and improved compression. I am not having any issues just figured I'd do some maintenance. I only run the Ultra oil so hopefully that would help keep the carbon in check. I put a bore scope in the cylinder of the pole saw and the top of the piston and the cylinders walls were very clean and looked good as did the plug, I could not see the valves.

 

[ZeroJunk]

That's just not been my expiereance in regards to head wear, Zero.
I have a friend that's been doing lawncare since the 90's. He hasn't noticed it either.
I've only had one head ever fail and it was on a Stihl FS85 that was
ran with a brush disk extensively By hired hands. Brush disks are much harder on the head as your constantly banging the disk into saplings at full throttle.

I have never worn one out either, even using a saw blade. But, I sure replace a bunch of them.

 

[HansFranz]

That's just not been my expiereance in regards to head wear, Zero.
I have a friend that's been doing lawncare since the 90's. He hasn't noticed it either.
I've only had one head ever fail and it was on a Stihl FS85 that was
ran with a brush disk extensively By hired hands. Brush disks are much harder on the head as your constantly banging the disk into saplings at full throttle.

I've had several gear heads come unglued, mostly on Craftsman trimmers. (Just got my first Stihl trimmer this year, in part because of the failing Crapsman heads.)

Seems like the housings flex/get loose enough for the beveled gears not to mesh properly, and after that it's all over but the crying...

 

[stihltech]

So how many have I de-carbonized since they came out? One, It made no difference.
What will make a difference? Regular replacement of the air filter, a tune up, proper valve adjustment and 50 to 1 mix. Ultra was made for these machines.
And yes, I service many pro users.
If you run half throttle a lot, there is much more chance for carbon. But that goes for any machine that requires 2 cycle mix.
It comes down to maintenance and proper operation. Same old story.

 

[bwalker]

I've had several gear heads come unglued, mostly on Craftsman trimmers. (Just got my first Stihl trimmer this year, in part because of the failing Crapsman heads.)

Seems like the housings flex/get loose enough for the beveled gears not to mesh properly, and after that it's all over but the crying...

I haven't run a Stihl trimmer in a few years, but the Redmax trimmers I have now have very deep and long splines. You are not going to strip one out.