066 Just stops. What gives???

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Southern Boy

ArboristSite Lurker
Joined
Aug 24, 2006
Messages
26
Reaction score
2
Location
S.E. Kansas
I was working on milling some walnut today and was just getting started. I was seeing what I needed to change, but the saw seemed to be getting REAL:blob2: :angry: :blob2: hot and then would just stop. Anyone have any ideas at what is up?:bang:

I used exactly two gallons of gas and mixed with Stihl mix for two gallons. Seems to be oiling the bar good and it seems to cut good, but just stops.

Thanks for any and all help.
Kris
 
Does it just stop after running how long?

Does it start?

When it stops does it rev up then conk out or just die slowly?

What's the air/fuel mixture like, if it's too lean and the saw is screaming could be the piston has seized in the bore.
 
This is from what I've read, but only that. I have no experience with it but make sure your saw is running on the rich side. There is a difference in how you set a carb for regular cutting and how you set it for milling.
 
2 gallons of gas is a good workout for the saw... not "just getting started". If you did not readjust your carb to quite rich (say 11k WOT) and run an oiler mix (say 32:1), you might have a problem. Pull the muffler cover off and look at the exhaust side of the piston.

A saw is designed for intermittent use, not the 100% duty cycle (i.e. full power for a full tank) milling demands. Part of the reason for richening up the mixture saw is to reduce the max HP output to something sustainable. I'm guessing on mine that it's running at about 80%. If you run it continuously at 100%, it will overheat and something has to give.
 
here is a quick question for thall or the rest of the stihl heads here. Say i where to buy a new ms660 from my dealer and dedicate it to the alaskan have them set it to say 11,500 max and the piston still scores in the first 90 days is this covered under stihl's waranty?? Any of the Husky knowlegeable chime in here as the 395xp and the 660 are the two i am looking to buy. And yes i know the Husky has a 24 month consumer waranty vs. the Stihl 90 day waranty that may very well loose the sale in the end for the stihl.
 
Lakeside53 said:
2 gallons of gas is a good workout for the saw... not "just getting started". If you did not readjust your carb to quite rich (say 11k WOT) and run an oiler mix (say 32:1), you might have a problem. Pull the muffler cover off and look at the exhaust side of the piston.

A saw is designed for intermittent use, not the 100% duty cycle (i.e. full power for a full tank) milling demands. Part of the reason for richening up the mixture saw is to reduce the max HP output to something sustainable. I'm guessing on mine that it's running at about 80%. If you run it continuously at 100%, it will overheat and something has to give.
This leads to a question Ive had for awhile, will mixing a little richer, say 32:1 vs 40:1, make a saw last longer? Or a waste of oil for a saw mainly used for clearing a road right of way, or firewood? Prob:deadhorse: here, but just curious
 
madmax said:
Prob:deadhorse: here, but just curious

Yes you are...but I will bite. Tons of posts on oil mix ratios, what oils to use, where to buy the oils, blah blah blah. 32:1 = more oil, less gas per unit volume. If your saw/carb is adjusted for 40:1 and then runs 32:1, it is now running the saw leaner. Oil lubricates, the incoming/fresh charge of fuel "cools" the saw, and the rings transfer the heat to the cylinder walls for removal. Less fuel makes the saw hot (lean), the hot saw then eventually flashes the oil that lubricates the rings, the hot rings become hotter due to increased friction as there is no oil, the rings and piston expand due to increased heat, piston melts, saw stops. Adjust your saw to run on 32:1 and you will be fine. IMO, 32:1 is more oil than needed though - resulting in SMOKE and WASTE. But, different strokes for different folks...40:1 works for me.
 
upandcommer said:
here is a quick question for thall or the rest of the stihl heads here. Say i where to buy a new ms660 from my dealer and dedicate it to the alaskan have them set it to say 11,500 max and the piston still scores in the first 90 days is this covered under stihl's waranty?? Any of the Husky knowlegeable chime in here as the 395xp and the 660 are the two i am looking to buy. And yes i know the Husky has a 24 month consumer waranty vs. the Stihl 90 day waranty that may very well loose the sale in the end for the stihl.


The dealer can't make a non-standard adjustment then expect the manf. to stand behind it. If you buy anew car, then drive it tankful after tank full at full power up a hill without a break, the car manf, isn't going to give you a new engine. I wouldn't mill with any saw until it's completely broken in.

It's not the length of the warranty that matters - it's the number of claims that result -and most pro saws have very few claims.. like 1 in a 1000 for stihl and I have no reason to believe it's any different with Husky).

Very few claims for scored pistons are received by Stihl, and of those, very few are paid out... Same I hear for Husky... Baring some weird component failure, it's hard to score a piston unless you do something that saw wasn't designed for, abuse it, use the wrong gas, set the wrong mixture etc etc

Asking the dealer to set the mixture and then you just mill away is not the answer to the question of whether that is sufficient to guarantee the saw won't fail... You have to be "in tune" (no pun) with your saw - listen to it, adjust frequently etc etc, let it cool off, not run out of gas, and generally treat it with some care. Milling is rough on saws, but they do last if the user understands the issues
 
upandcommer said:
here is a quick question for thall or the rest of the stihl heads here. Say i where to buy a new ms660 from my dealer and dedicate it to the alaskan have them set it to say 11,500 max and the piston still scores in the first 90 days is this covered under stihl's waranty?? Any of the Husky knowlegeable chime in here as the 395xp and the 660 are the two i am looking to buy. And yes i know the Husky has a 24 month consumer waranty vs. the Stihl 90 day waranty that may very well loose the sale in the end for the stihl.

Hmmmm thats a interesting question. Beings you would come in and be totally honest about what your going to do with the saw I would in kind be totally honest with you. You can't take a brand new saw and toss a mill on it and set the rpms low and go, doesn't quite work that way. I go by the book on new saws. I usually set the rpm level 1000 r's below max and tell you to bring it back after you have run it awhile. Stihl claims it takes a full 5 gallons of running to actually break in one of their engines. You do that and bring it back and then I check the R's and make sure they are within specs and usually they are, they tend to increase about 500-800 R's after breaking in, if not I reset it.
After that you can go milling with your saw providing you understand milling is very very hard on a saw. Lakeside can give you all the guidelines you need about milling and how to set your saw up correctly and how to use it correctly as well.
As for should the piston fry, which is easliy done milling and most times due to operator error(running full throttle way too long,overheating) and the saw not set up correctly(richer mix to slow it down for constant heavy cuts) that would be a tuffie. I can't tell you for certain whether Stihl would cover that or not because I simply don't know. I can say this. I would indeed hop on the phone on your behalf and explain you did everything beforehand to set the saw up for milling and it fried. My distributor rarely ever tells me no on warranty but I've never called about a saw used for milling. I don't know what they're responce would be on that.
If I were you, and you seem to be totally upfront about what your doing with the saw, tell your dealer ahead of time. Have them call Stihl and find out exactly what is the deal for using a 660 for milling. They will surely explain to your dealer the whole nine yards and he will in turn tell you. You go from there. I don't think neither Husky or Stihl will mis-inform you about their policy concerning milling. Best way to find out is merely have your dealer call ahead for you.
 
Southern Boy said:
I was working on milling some walnut today and was just getting started. I was seeing what I needed to change, but the saw seemed to be getting REAL:blob2: :angry: :blob2: hot and then would just stop. Anyone have any ideas at what is up?:bang:

I used exactly two gallons of gas and mixed with Stihl mix for two gallons. Seems to be oiling the bar good and it seems to cut good, but just stops.

Thanks for any and all help.
Kris

Key words there "SAW SEEMS TO BE GETTING REAL HOT" not good. Pop the muffler and see how hot it really got. If theres no scoring your lucky, you have other problems. Pop the muffler first, only a 5 minute job and have a look see before going any farther. Those key words you used usually lead to a scored piston, cross your fingers...
 
I'd be taking the instruction manual to a lawyer and suing Stihl if they didn't cough up.

Find me where it says not to use it for milling?

If the saw is run in, set up correctly and siezes then that is a manufacturing design defect. They should have plastered across the book in huge letters NOT DESIGNED FOR MILLING.

Otherwise they aint got a leg to stand on.

If overheating was an issue then they'd have to design in some protection, rev limiter, heat murphy switch etc.

Whilst I dont mill I have many times run full tanks of juice thru the 66 ripping logs and fence posts, tank after tank, no problem, but the saw wasn't on it's side.

Doing this with a 46 once the saw seized, bam, dead silence. I knew it was bad, took it to the shop and they pulled it down. Rings failed, one got stuck between the piston top and exhaust port, broke the crankshaft!

Saw was sent to Melbourne and full rebuild free, oil, fuel etc was all withing spec, colour of plug was good, they could not fault the user so they have to cough up.

Be tough, they have a lot more money than you, and fixing your saw is the best advertising they could do.:)
 
Ekka said:
I'd be taking the instruction manual to a lawyer and suing Stihl if they didn't cough up.

Bah... that's crap. They don't tell you not to slice cheese with it either. Go ahead and sue them because your grilled cheese sandwich tastes like bar oil. :angry:

Ian
 
Sorry for not getting back to you guys sooner. Thanks for all the great info.

To answer some of the questions.

How long?
Running about 1-3 minutes at full throttle and total run time approx. 5 minutes

Does it start?
It will after I let it set for a while?

When it stops does it rev up then conk out or just die slowly?
Just dies slowly when I let off the gas.

How hot?
Smoking hot!!

What's the air/fuel mixture like?
I don't know. How would I go about checking it? I'm not a great small engine mechanic.

I was only using a lumber maker and working on a small cant approx. 5' long just to practice.

I bought the saw used and have only run close to two tanks through it.

I'll take the muffler off tonight and check it. I think I'll print this discussion out and take my saw down to my local Stihl repair shop and have them look at it and adjust based upon the suggestions here.

Kris
 
Last edited:
Ekka said:
I'd be taking the instruction manual to a lawyer and suing Stihl if they didn't cough up.

Find me where it says not to use it for milling?


Where does it say in your car user manual that you can't go racing with it?? Where does it say you can't use your food mixer for mixing concrete?

In the USA. EPA and CARB regulations prevent a dealer or stihl (or end-user) from adjusting a saw "so it's suitable for milling". Won't stop many from doing it :) but...

HA! good luck with the lawyer! Lots of laws that protect the both consumer and the manufacturer, but milling is not an "intended purpose".

Thall's correct. If you ever have a problem with a saw, be up-front with your dealer. I will go to bat for the guys that are honest with me, but try to BS me, - hand over your wallet or go somewhere else.
 
Southern Boy said:
Sorry for not getting back to you guys sooner. Thanks for all the great info.

To answer some of the questions.

How long?
Running about 1-3 minutes at full throttle and total run time approx. 5 minutes

Does it start?
It will after I let it set for a while?

When it stops does it rev up then conk out or just die slowly?
Just dies slowly when I let off the gas.

How hot?
Smoking hot!!

What's the air/fuel mixture like?
I don't know. How would I go about checking it? I'm not a great small engine mechanic.

I was only using a lumber maker and working on a small cant approx. 5' long just to practice.

I bought the saw used and have only run close to two tanks through it.

I'll take the muffler off tonight and check it. I think I'll print this discussion out and take my saw down to my local Stihl repair shop and have them look at it and adjust based upon the suggestions here.

Kris

You may be o.k.... "Smoking hot" is often a perception...

You need to check the airflow path - in through the recoil, flywheel, and out through the cylinder fins. Clean out all debris, and it it's coated/baked on the cylinder fins, clean it all off.

If your carb or fuel hoses are faulty, running the saw on its side may have contributed to a lean condition.

It may also be just running too rich (L) - as it got hot the mixture was too rich for the cyliner temperature. That's an easy fix...


Pull out your plug - Is it black, White, or tan? Is it coated with a gray gritty substance - that's your piston if so...
 
Lakeside53 said:
It may also be just running too rich (L) - as it got hot the mixture was too rich for the cyliner temperature. That's an easy fix...

I'm not too familiar with 2-cycles yet but if it is running hot isn't that normally a sign of running lean not rich?


Check to make sure the gas tank is being vented properly. I bought a used saw that ran strong for 3-5 minutes and would die when I let of the throttle. The vent that lets air back into the tank was completely plugged. Just fixed it this weekend and so far so good.
 
In fact, you'd just pass the case over to Dept of Fair Trading here and the govt would persue it. It's illegal for both manf and resellers to promote a product to do something it is incapable of, snake oil.

Running a few tanks of juice through to mill is far from abuse.

Like I said, they rebuilt mine.

Stop comparing cars and cement mixers to chainsaws, they're not 2 strokes.

The question has been raised and asked before about 2 stroke performance, they're either flat out or at idle and not designed to perform at half throttle .... that's from the very saw guys themselves, do some searches.

I have noticed the same with 2 stroke brush cutters and lawnmowers, there's one speed, flat out. I had a Kawasaki straight shaft brush cutter, it had a half throttle lock which I used a lot for inverted edge trimming instead of holding the trigger. The engine carboned up and had to be de-coked, the dealer told me to run it flat out, that's what they're designed for.

This does not mean you dont warm up or cool down your saw either, that's common sense and there's some words about that in the manual.

If in fact at normal settings and r's the saw on a hot day siezed after repeated tanks of fuel then you wouldn't have to be Einstein to figure out that the piston/ring tolerances are too tight to the bore or the cooling system inadequate. Some-how I think companies like Stihl and Husky would have done those trials.

It's hot here often, on some land clear jobs I've had that 66 ripping for hours, never missed a beat. But like I said it's not lying on it's side .... if that does make a difference.

:D
 
I was using a "lumber maker" style of jig and that holds the saw upright. The whole time I ran it yesterday, it never was on it's side. I'm not getting into a which one is better, but my Jonsered 2050 Turbo took the big Stihls place and never missed a lick. The Jonsered even has a regular 30^ chain where the Stihl has a ripping chain. I was just let down by the big saw, but as stated earlier, I know little to nothing about small engines.
 
Well that's good news, thanks for that post. I'm a little inquisitive bugger that asks a lot of questions, you'll learn a lot in life doing that.

I think you have answered the question, take the Stihl back to the dealer and have it checked if it's within the warranty period, dont get pushed around by them either.

My first hunch was air/fuel mixture ratio, that has to be set correctly. I set my own by ear, running slightly rich. On the side of the saw is some small holes for a screw driver to be passed thru which turns the adjustment screws.

Turning them in is leaner and out is richer.

The "L" screw stands for LOW (idle mixture) and "H" stands for HIGH. You'll see a little 1 or number there, that means the default setting is a certain amount of turns out (anti clockwise) from the full in position. So if you see next to the H a 1; screw it all the way in, then wind it out 1 complete turn. That'll bring you close to the mark but you may need some finer adjustment.

I usually turn slightly more out so the saw occasionally 4 cycles, you'll here the saw run slightly less rpm's but sound a little different and not scream as much. It will tend to 4 cycle under load.

Another more accurate way is using a tacho to set the r's, you wind out till you hit the r's recommended for that saw.

Off topic, about 6 months ago I bought a new PC that kept breaking down, after nearly 3 months of repairs and BS from the PC shop I requested a refund, of course they declined saying it was their right to repair. Of course it is their right to repair but it's also my right to have a decent working PC. So they replaced with another model. Well, that replacement was no different, multiple breakdowns. I finally said I was taking the matter further and going to Dept of Fair Trading here as the law prevented the type of conduct they were displaying, within 7 days I had a full refund. Went elsewhere and got a darn good PC.

Moral of the story is if you have done the right thing so should they.
 
Thanks for all the great help. My delima is I bought it used off of ebay. A person runs the risk when they do that and have to weight out the odds based upon the sellers feedback and what type of auctions they normally run. I felt pretty safe with this seller and I pulled the trigger. I may have gotten burned, but if I did, it would be the first time I have on ebay.

Tonight, I'm going to:
1. take the muffler off and check the piston.
2. Pull the plug and check it out.
3. I'll try and adjust the high speed mixture.
4. change the mix from 50:1 to closer to 32:1.

If I don't get it to a point I feel confortable, I'll be at the saw shop at lunch tomorrow.
 
Back
Top