Stihl 084 Carb Adjust

[Frank Boyer]

I need to adjust the carb on my 084, serial number 115595439. Is 10500 RPM a good number for the high side. How do I tell if I have a rev limiter ignition? How does the rev limiter change the carb adjust? I have a tach.
THANKS

 

[blsnelling]

Factory spec is 12,000. Some are limited, the three I've had have not been. You will be able to tell by watching the tach when you tune it.

 

[hoss]

It may not just be the ignition. These saws should do a comfortable 12,000 rpm but some have the two lead (limited) coil and some have the ht3, ht5 etc carbs wich are limited by the seat for the high needle so the jet will notlean all the way out. You can buy new jets or make suer that you have an HT-1 carb wich is fully adjustable. My 084 had the non limited coil but wouldn't top 10,500 rpm so when I got in touch with stihl that is when I learned about these limited carbs. I ended up tracking down an HT-1 wich solved the problem, but I have been told that you can change out the jets on the later ht series carbs (don't know if it works though). Now mine turns about 12,200. Keep in mind though when I talked with stihl they said that the limited saws should not run any different IN wood, that it was only tuning out of the wood where there would be a difference. So it seems that for normal use it shouldn't make a difference, but if you were going to race obviously you would want a non limited saw.

 

[Frank Boyer]

I am not going to race. I just want the saw to cut wood. I have some very dry 36" diameter tan oak that needs to become fire wood. I'll work with it today.
THANKS for the info.

 

[blsnelling]

Setting it up at 12,000 is not akin to racing. That's the factory spec where i's supposed to set for normal use. Any richer and you're just carboning up the saw.

 

[teacherman]

Setting it up at 12,000 is not akin to racing. That's the factory spec where i's supposed to set for normal use. Any richer and you're just carboning up the saw.

12,000? I'd be afraid the thing would lift off into orbit at that speed, as big as it is......

I'm sure milling would demand a lower tuned speed, right?

 

[Lakeside53]

I would... Detune it for milling. Running a saw at continuous max HP is not going to enhance life.

 

[blsnelling]

12,000? I'd be afraid the thing would lift off into orbit at that speed, as big as it is......

I'm sure milling would demand a lower tuned speed, right?

That's what your's was set at when you got it.

 

[blsnelling]

I would... Detune it for milling. Running a saw at continuous max HP is not going to enhance life.

For milling, yes. But I didn't see where he was milling.

 

[teacherman]

No, I havent done any milling. I also haven't changed any settings on it either.
I put thetach on it and check it out. I am not speaking from any place of great knowledge here, just seems like a high speed for a big ol' chonkin' saw like that to be turnin', that's all. Purely subjective here.:chainsawguy:

 

[blsnelling]

Mine saw 13,750 when I was tuning it after the port work:jawdrop:. I detuned it to 13,500. I haven't retuned since putting the popup piston in it.

 

[Frank Boyer]

I wasn't sure what number to use. The owner's manual says 12K and the shop manual says 10.5K RPM. Since this is an older saw, the "book" numbers are often changed based on real world experience. It is an occasional use saw and "working hard and staying together' is the main objective.
THANKS

 

[blsnelling]

I didn't know about the shop manual setting. However, the three I've worked on would have been set at 12,000-12,500 when set by ear, confirming the 12K spec in my mind.

 

[hoss]

My second one was limited to 10,500rpm by carb (had the three pronged non-limited coil already).

 

[Frank Boyer]

I set it at 10.5K RPM and it ran strong. I was cutting very dry 36" tan oak with a 36" bar. I switched over to a 460 for the 24" log and I couldn't believe the difference in power. There is no substitute for cubic inches, but they sure are heavy
THANKS for the help.

 

[hoss]

I set it at 10.5K RPM and it ran strong. I was cutting very dry 36" tan oak with a 36" bar. I switched over to a 460 for the 24" log and I couldn't believe the difference in power. There is no substitute for cubic inches, but they sure are heavy
THANKS for the help.

Yeah, that's what stihl told me. They said that no load WOT might not be what I was used to but that it was designed that way and would be just fine in the cut.