MS 170 turning 14700 RPM's

[Jtheo]

Idling at 36400 and hitting 14700 on the top.

This is a bit above what the book says.

It has to be lean to hit that RPM, right?

Should I take it back to the dealer or run it?

Am I likely to score a piston?

The mix is 92 octane ethenol free and 40:1 Stihl regular oil mix.

This saw is about a year old and has not been worked all that much.

It went to the dealer a week ago because it would not keep running. I was told that it was running at half coke all the time and was now good to go.

Didn't pan out though. I ran the saw for about 30 minutes and then it quit and would not start. After it cooled down it would start but not idle.

I screwed in the LD screw until it seated, and then out 2 turns like the manual said.

It idled fine, and I decided to check the idle speed and top end.

That's when it hit 14700, I checked it several times with the same result, and then checked another saw with the tach. The 346XP hit 13500 which is what it is tuned to, so I think the tack is working right.

This saw has a fixed jet in the carb.

A lot of you know much more than me. What do you think?

 

[blsnelling]

Yes, that's more than what it should turn. However, I think you will find that most of them turn that high. You can thank the EPA.

 

[eMGunslinger]

14.7k isn't bad, I would take it down more if it were a work saw just for longevity but 13-14k isn't uncommon

 

[blsnelling]

14.7k isn't bad, I would take it down more if it were a work saw just for longevity but 13-14k isn't uncommon

The problem is that they're not adjustable.

 

[eMGunslinger]

The problem is that they're not adjustable.

O its one of....those (ill just take my spot in the backseat now):hmm3grin2orange:

 

[blsnelling]

O its one of....those (ill just take my spot in the backseat now):hmm3grin2orange:

The only solution I know of is to graft in an adjustable 025 carb. It's a simple mod and works great.

 

[wigglesworth]

Take the metering lever and bend it up just a bit. She will settle back down to normal RPM. I've been down that road before. However, if you got her hot to the point it shut down u need to pull that muffler off and have a looksie....

 

[ironman_gq]

Changing to a 50:1 mix might help a little. I know it is less oil but it is also more gas for the same amount of mix used.

 

[Jtheo]

I appreciate all the replys.

Here is what has happened so far. I talked with a Stihl Tech in Virginia and he suggested that I take the saw to my local dealer and have a leak down test done.

If it is not sucking air, then the carb will need to be replaced. He told me to have the mechanic call him with the results of the test.

I also found out something that most of you probably already know.

The flip caps have been improved and any older ones giving trouble will be replaced at no charge to the customer.

I will likely buy another MS 211 this Fall, since I found that out.

I sold my first one because of so much trouble with the caps leaking.

 

[Jtheo]

The only solution I know of is to graft in an adjustable 025 carb. It's a simple mod and works great.

Brad, I like that idea, and I might end up doing it.

First I am going to check out the 192CE, and if I like what I find out, I might sell both the 170'2 and buy the 192.

I just need a good light weight saw for brush and pruning fruit trees, and I need good dealer support.

 

[Jtheo]

Take the metering lever and bend it up just a bit. She will settle back down to normal RPM. I've been down that road before. However, if you got her hot to the point it shut down u need to pull that muffler off and have a looksie....

I think Stihl is going to fix this saw under warranty. If not, I will try your suggestion on the metering lever.

I did look at the piston and cylinder through the exhaust port, and I see no scoring.

Thanks for your help.

 

[spankrz]

i would suggest running the saw 50:1, as stihl reccomends to start. however, that would not cause your problem.

if you dont have an air leak, it is carb time

 

[Jtheo]

Here's the lastest on the 170.

I just got a call from the dealer's shop. The carb found to be defective, and was replaced by an updated version.

That is good fast service, and it increases my confidence in Stihl.

Thanks for all the input on this guys. It is appreciated.

 

[blsnelling]

Take the metering lever and bend it up just a bit. She will settle back down to normal RPM. I've been down that road before. However, if you got her hot to the point it shut down u need to pull that muffler off and have a looksie....

Excellent tip right there. Thanks Jeremy!

 

[C George]

i would suggest running the saw 50:1, as stihl reccomends to start. however, that would not cause your problem.

if you dont have an air leak, it is carb time

a little more oil will never hurt

 

[261cm]

a little more oil will never hurt

What he is trying to tell you is by running more oil on a fixed jet carb you ARE leaning out the air/fuel ratio which is not adjustable on your saw. Quality oil will run at 50:1 without a problem, and should be what you run. So actually in your specific case more oil can hurt.

 

[Dean-O]

Idle is at 36400? Might be a tad high……