Max RPM from Factory setup

[JohnCusickjr]

So, just got my DTI-20K tack in anticipation of a muffler mod on a 440 I planning.
I decided to check a few of the saws that we've been using intermittently over the last 4 months while reviewing the tach's operation. Interesting...
Had just cleaned all filters, bars and reset chains this weekend past during the snowy 2 day mess.
My new 361 (purchased 10/06) came in at 14,900 repeatedly, H screw all the was cc.
My 6 month old used 361 SAME...H screw maxed out.
My new 440 (7/06) 13,900.
The only one that came in under max spec was the 200.
What's up with these setups.... I called my dealer ready to scream...
I get impression that you NEED to be able to check and recheck all work....
No big deal in the long run, PROVIDING I haven't hurt anything.
AGH>>>
THanks to all who give of their time to educate ones like myself...

just a carpenter....

John

 

[Goat]

Remember, the spec is +/- 1krpm. I wouldn't be surprised if they did some mass adjustment, based on some data from a sample set. At least that is how they balance car engines.

 

[Lakeside53]

They are actually real close... Maybe a 1/32 turn on the H to bring them down to "spec". Be careful with The Stihl PUBLISHED max rpm.. The saw is set to the correct mixture at the factory, but the max rpm can vary plus or minus 1000... changes in weather, gas, bar length, chain tension etc. Get rid of the alcohol in your gas (if available in your area).. the numbers will drop,

Max rpm WOT is just a crude approximation of the correct mixture..

Measure them tommorow - they will likely be slightly different!
If they were my saws, I'd take them down a little - stay away from the edge...

 

[Lakeside53]

Remember, the spec is +/- 1krpm. I wouldn't be surprised if they did some mass adjustment, based on some data from a sample set. At least that is how they balance car engines.

They take one in 250 from the line for a ful EPA test; if it fails, the entire 250 get reworked. Saws for Califormia are EPA checked at the rate of 1 for each 100.

 

[JohnCusickjr]

Thanks. I can sleep tonight and not worry that I've trashed a load of saws...
OK, now to remove the limitercaps to get some room for the rich side adjustment.
Though thats what seems bogus about this setup. Sure would be NICE if they left you a wee bit of room on the rich side to tweak the adjustment WITHOUT having to pull the caps...
Cleaning the bench to begin...

 

[stihl 440]

Wow!

So, just got my DTI-20K tack in anticipation of a muffler mod on a 440 I planning.
I decided to check a few of the saws that we've been using intermittently over the last 4 months while reviewing the tach's operation. Interesting...
Had just cleaned all filters, bars and reset chains this weekend past during the snowy 2 day mess.
My new 361 (purchased 10/06) came in at 14,900 repeatedly, H screw all the was cc.
My 6 month old used 361 SAME...H screw maxed out.
My new 440 (7/06) 13,900.
The only one that came in under max spec was the 200.
What's up with these setups.... I called my dealer ready to scream...
I get impression that you NEED to be able to check and recheck all work....
No big deal in the long run, PROVIDING I haven't hurt anything.
AGH>>>
THanks to all who give of their time to educate ones like myself...

just a carpenter....

John

I think 14,900 rpms is a little much for a 361 brand new(not broke in). 13,500 would be more like it, before break in. Even if it is broke in, that is a little shaky.

 

[JohnCusickjr]

Ans I've NEVER touched these carb adjustments.
I agree, they scream when NOT loaded, the few brief times that's happened. Fortunately they are always in the cut and working when the trigger is pulled.

 

[Lakeside53]

Yes... the "scream" is a user controlled issue... and has little to do with "correct mixture". If you're worried, set them back. New pro stihl saws have very fine bore hones.. very little issues with break in.

EPA requires a very lean mixture to pass unburnt HC emmissions... and this is how they are set at the factory - full CC on H, right against the limiter.

BTW... I get 200T all the time pulling 15,000... and get complaints when I set them back... Not sure they cut any better than at 14,000, but...

 

[Nicholas]

Go to your friendly Stihl dealer and order a carb limit cap removal tool and a bunch of new carb limit caps. Remove the existing limit caps from your saw. Take the new limit caps, shave the tabs/projections off with sharp razor blade, and install. Tune like a normal saw.

Nick

 

[Goat]

They take one in 250 from the line for a ful EPA test; if it fails, the entire 250 get reworked. Saws for Califormia are EPA checked at the rate of 1 for each 100.

That's kinda what I figured.

I still have hell of a time tuning a saw by ear. All it's good for is telling me that something is amiss.