Recommended Max WOT rpm’s for an MS170? Please!

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Schipp

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Can anyone tell me?
I have the 14” bar and 3/8 .050 chain, WT-215 carb with the H & L carb adjustment screws! (Cheaper $10 Qazaky brand carb) ) (Brass plug out and side hole plugged) MMod’ed (plus a stock muffler, to test the difference)
I can’t get it adjusted right by ear!!
My ms250’s I have no problem hearing when I’m “tuned to the wood”! (Four strokes when I lift out of the wood)
I received my Tiny Tach DTL-100 tachometer today!
My Stihl Manuel doesn’t tell me what the rpm’s should not exceed! And I couldn’t find it on Stihls official site!
I’ve searched and found where BSnelling mentioned wot rpm’s for the ms180...But can’t find it for the 170! (Is it the same?)
If anyone knows or has an idea for the recommended max rpm’s at wot AND for idle speed I would greatly appreciate your input!
Right now when I tune it by ear to what seems close to right the:
L is out about 2.5 turns and the:
H is only out about 3/4 of a turn! (But I lose power in the cut) (I put on two different new carbs and end up with the same adjustment)
That doesn’t seem right!
I start with one full turn out for both the H & L
and will not run!
I’m using brand new 40:1-50:1 premix from Walmart until I get it figured out! (I normally run 45:1 non-synthetic)
Brand new ms170 that ran great with the stock carb! But it wasn’t four stroking at wot before a cut, so I know it was lean!
Again I have no prob tuning my ms250’s or my Echo 600P! Or others saws that I’ve had, but having trouble getting this one dialed in!
Thanks so much in advance for your help!!! ☺️
 
Should be the same as the 180, they're essentially the same saw.
Ok, thanks! I’ll shoot fer around that!
The Tach is helping me gettin it to run better...but the saw dies when I turn it on it’s left side! (Fuel cap side down) Diaphram prollem?? (Both those cheap carbs did that) I may end up getting a $30 Walbro wt-215, just to check off that possibility! (The cheap carb works great on my older 025 that didn’t have a H screw on the stock carb)
Also when it dies, I have to full choke it and pull once, then up a notch and pull three or four times before it starts, no matter how long it’s been running! (Which doesn’t really bother me if I can get it runnin right!)
And the choke lever won’t stay down in the “Warm choke” position because the air filter body hits the throttle linkage because the wt215 carb throws the linkage a tad higher!
I did block off that hole in the air filter body that the 90° on top of the stock carb poked into...even though it looks like it’s a closed hole!
Can I take that top cap off the stock carb and put it on the wt-215, so that that 90° that’s on top of the stock carb now, will fit back into the hole in the air filter body? I might try that, eventually! Ok, thanks again!
 
Page 52 of the owners manual.

ISO 7293: 8,500 rpm
Idle speed 2,800 rpm
I SEE THAT!!!
THANK YOU!
I overlooked that!
What does “ISO 7290” mean?
Looks like I have it high!
Let me mess with it some more!
 
Look closely at the fuel line, especially if it is one of the old black ones...

Look for cracks, and/or soft-gumminess.
Ok! Thanks! I haven’t thot to check that because the saw is brand new and ran like it should, stock! I don’t think I ran a whole tank out before I changed carbs!
Stihl has a sale on them for the rest of June 2019 for $159.00
 
To answer your question based on my pirated info for Stihl saw specs that I got off the internet for an ms 170 is 2800rpm idle , 14,000 rpm max.

I never worked on an ms170/017 till recently when I was assigned the task of making a runner from basically one complete junker and two donor saws. I got a runner from all these different part saws but the one thing that was a different experience for me was all three of these carbs were totally non adjustable , no H or L screws, only the idle was adjustable. Anyway the runner I got had no problem coming close to 14000 max rpm or so it sounded to my ear and didn't sound all that lean . I didn't tach the saw because it wouldn't do any good because I couldn't adjust it. The only thing I did to the muffler was leave the spark arrestor screen out of it.

My info for a regular 017 only gives the idle and that one is 3200 rpm and no number for wot. I don't know what is up with this .

I have some info on the carb settings but it isn't all that helpful , basically for Zama carbs , no limiter caps 2 turns out on the L , no info for the H. A Walbro carb same deal with no limiter caps is just 1 turn out on the L, no info for the H setting.

I don't know if this helps you or not.
 
Thanks Harley , You got me updated on the spec sheets and other good info I didn't have.
 
No problem . You have been so helpful sharing info that I had to transfer some of the past info to a J -drive because I was running out of storage room on this computer.
 
ISO generally stands for International Standards Organization. It’s an international accreditation moniker that shows you have achieved “superiority” in your manufacturing standards. It is used by many companies as a minimum standard before they will do business with you or you with them. Much of it is BS.
 
Ok! Thanks everyone!
I finally got it runnin pretty good!
It is a nice little runner now! (I still need to fine tune though)
I cut about a truck load with it! Startin to kinda “hear” how it sounds!
I have low idle a little higher than 2800 I believe!
And I believe wot is closer to 11,000 right now?
I’m still gettin used to that Tiny Tach! It fluctuates quite a bit! I guess you kinda have to take the average of what it’s showing you!?
BUT I have the H side almost closed-closed and it STILL seems like it needs to be leaner!?
Anyone ever run into that?
Does that mean I have too much airflow? Idle screw need to be closed more?
I’m really trying to learn how all three adjustments affect each other! (Any good videos on this???)
I put the top from the sto’clock carb with the 90° “fittin” on top over on the wt215 “knockoff”! Then when I started it..it ran like a “scared haint”! Couldn’t slow it down! Had to kill it! So I stuffed that hole on the “fittin” up! BUT, I think maybe my throttle linkage was stuck where I bent it trying to make it work ..better!
I replaced it with another new linkage (thank goodness I ordered two) but left the hole plugged!
Now it’s runnin close to perfect, I believe!
Still need to tweak it tho! I’m havin fun learnin!
I’ll mess with it more mañana! ☺️
 
The higher rpm does sound better. Odd Stihl would document the low idle but not wot. Guess I new what ISO was, I work in manufacturing and have had classes on it but don't see the relationship with chainsaw rpm. Only thing I can think of is 8,500 is the standard minimum.

Glad you got her tuned in.
 
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