Author Topic: Cooked two MS660s in two days! (Read 8769 times)

OneWithWood · « **on:** September 03, 2011, 02:52:56 PM »

Some days it doesn't pay to get out of bed...

I purchased a new MS660 to use with a Grandberg mini mill to split some large red oak logs for milling. The log I started on is 38" in diameter and has sat in a yard since April. I fastened my guide rail to the top and proceeded to rip it down the middle with my MS460 equiped with a 32" bar and ripping chain. I got halfway throught the log before the saw got hot and quit. The cylinder was scored. I assumed I was just asking too much out of the 460. Well the new 660 with the same bar and chain lasted about 10 minutes before it suffered a similar fate. The new saw still had the fuel and synthetic oil from the dealer in it so I know it was not fuel related. I took it back to the dealer who determined it must have had a bad seal from the factory and ordered another saw under the warranty.
I got a little further with the replacement. I put on a 38" bar with RMC chain and cut a number of cookies of an equally large log then put the 32" bar with ripping chain on it and proceeded to finish ripping the first log. I finished up the first cut, rolled it over, affixed the rail guide and got half way through the length of the log before the saw suddenly heated up and quit. Yup, scored that piston and cylinder too.

I took it back to the dealer. This dealer is a real gem, being very patient and working with me to sort this out. I explained what I was doing and what happened. Neither he nor I could come up with a reason for the saw failures. I wondered if milling full out in a vertical position was somehow causing the saw to lean out. The dealer said it should not matter. He is contacting the Stihl rep who I hope will come out with another saw so I can demonstrate what I am doing. Something is definately not right and I need to get it figured out.

Any ideas?

wannabeonetoo · « **Reply #1 on:** September 03, 2011, 03:49:12 PM »

Maybe the new "Chinese" P&Cs Stihl is using aren't what they're cracked up to be ?

Just kidding............. (I hope!).
Sounds as though you have a great dealer ! When will the rep. be around ?

Steve

Buck · « **Reply #2 on:** September 03, 2011, 03:57:35 PM »

You definitely have an above average dealer.

ladylake · « **Reply #3 on:** September 03, 2011, 05:07:28 PM »

Give those saws more fuel for milling. Steve

John Mc · « **Reply #4 on:** September 03, 2011, 05:09:51 PM »

A lot of saws come set pretty lean from the factory. Did you (or your dealer) richen it up a bit? Ripping is a tough application for a saw. A little richer mixture helps it run a bit cooler. I don't know the 660... maybe it's one of the automatic adjusting mixtures?

Also, I wonder if you should run a few tanks of fuel through the saw in a less demanding application before jumping right in to ripping? Just asking here... one of our resident experts would know better than I.

John Mc

lumberjack48 · « **Reply #5 on:** September 03, 2011, 06:42:24 PM »

Trying to pull or push the saw just a little to fast in to a green [ wet] Red Oak. You can tell by the sound of the saw how hard its pulling, and if its pulling to hard to long it can't get rid of the heat fast enough, it will score the piston on the port side every time.

I hope they come out and run the saw it will be interesting, keep us in formed on this matter.

zopi · « **Reply #6 on:** September 03, 2011, 07:49:27 PM »

Hadda 660 do the same thing...just sawing....having it fixed now, gonna richen it up a bit....stihl is beginni.g to annoy me.

Collima · « **Reply #7 on:** September 03, 2011, 08:52:21 PM »

I run the stihl 880 with a 72" bar for ripping logs. I built my own Alaskan mill. I make a lot of wide live edge slabs. Used to use ripping chain, but went back to .404 chisel chain cause it's cheaper, easier to sharpen, and cuts good. Make sure you have an oiler on both ends of the bar! Crank the oiler all the way up on your saw too. Mix your fuel nice and rich. Keep the rpm's up. If your saw starts bogging down pull 'er back a bit. Other than that your saw should be able to handle it. Either your doing something wrong or the saws you got were defective. It should be able to do the job!
By the way, I need a dealer like yours!!

Old Iron nut · « **Reply #8 on:** September 03, 2011, 09:06:25 PM »

You might try using a heavier 2 cycle oil to gas mix in the saw. I fried a P51 Pioneer saw several years ago using Amsoil's 100 to 2 cycle oil. That stuff does not work in 2 cycle engines running 8500 rpm. Amsoil did not stand behind their product, said there was alcohol in the gas. We did not have alcohol or ethanol in our gas at that time. I finished the remaining 3-4 gals. that I had mixed up in a Lawn Boy mower. That thing never ran better. I am presently using a 16 to one mix in 100 octane av gas in my P41 and P52 Pioneer saws and have not had any trouble. Things run very well, don't have to pull the starter cord 20 or 30 times to get them going. At the time I fried the P51 the weather was very hot. This may have some bearing on your saws failing. I would question using synthetic 2 cycle oil in chainsaws. I am a firm believer in synthetic oil. Use it in everything here, including tractors. Hope you get your problem solved, man can't afford too many incidents like that. Needless to say, I will never use any Amsoil product again.

John Mc · « **Reply #9 on:** September 03, 2011, 09:58:15 PM »

Amsoil is actually a pretty good product... I just wouldn't run it at 100:1 as they advertise. Maybe I'd take a gamble in a weed-whacker, but not in a high-end chainsaw.

clww · « **Reply #10 on:** September 03, 2011, 10:04:15 PM »

I've never run a 660, but when I am ripping with my 084 or 090, I mix at 32:1.

shelbycharger400 · « **Reply #11 on:** September 03, 2011, 11:31:00 PM »

i have done some free hand ripping to break down some large logs in 24in dia. using 40 to 1, with quaker state 2 cycle (comes out of the can like syrup) the older craftsman definately gets hot at wide open (10-12000 rpm), but usually i back off a bit, and let it run at idle or a little off idle to cool down a bit

quietrangr · « **Reply #12 on:** September 04, 2011, 11:52:07 AM »

I run Amsoil Professional 100 at 70 to 1 and have had very good luck with it for about four years, cutting about four or five tanks a day. For ripping I'd make sure you're not revving too high, and richen up your oil to gas mixture, maybe try it at 32 to one, and break in a new saw on firewood or something less steady high demand than milling.

Ironwood · « **Reply #13 on:** September 04, 2011, 06:28:10 PM »

I just wanna subscribe to the thread.

Ironwood

Weekend_Sawyer · « **Reply #14 on:** September 06, 2011, 05:45:51 PM »

Yea, me too, I was just wondering today if anyone else replied to messages just be able to get notified of updates.

Jon

lumberjack48 · « **Reply #15 on:** September 06, 2011, 07:50:10 PM »

The Stihl Dealer told me to never run my Stihl's leaner then 32:1, never run a off brand oil, and absolutely no ethanol.
He knew how hard i worked a saw, i don't mean beat on them, i took top care of my saws every night, i blew them out, they got the full treatment, because in the morning it was off to the battle again, full throttle, i always set goals, and a battle plan, i couldn't have saws or a man lagging behind.

John Mc · « **Reply #16 on:** September 06, 2011, 09:55:20 PM »

Quote from: Weekend_Sawyer on September 06, 2011, 05:45:51 PM

Yea, me too, I was just wondering today if anyone else replied to messages just be able to get notified of updates.

All you have to do is click on the "Notify" button near the top right of the thread.

Weekend_Sawyer · « **Reply #17 on:** September 07, 2011, 05:59:59 AM »

True John, but this way I am part of the conversation.

Al_Smith · « **Reply #18 on:** September 07, 2011, 08:13:53 AM »

Well I'm not going to get into oil mix ratios because everybody wants to argue how much and what kind so run what you want to .

However if you are ripping ,milling whatever keep in mind that aside from stumping this is about a demanding of a task ever placed on a chainsaw .As such you have to run a rich carb setting .Lean fuel mix will run much hotter than rich .Too lean or even with a normal setting for average usage will not work out well on long rip cuts .

Then too in my opinion for the two cents it's worth seems to me that many have the bright idea they must cut lumber as smooth as if were ran through a table saw with a hollow ground cabinet blade so they use rip chain .Rip chains are slow,they pull saw dust instead of chips .To me they put undo stress on the saw where a standard old chisel will cut smooth enough for the purpose .After all if it is finish lumber it will be planed anyway .

lumberjack48 · « **Reply #19 on:** September 07, 2011, 12:12:35 PM »

Can't say it any better then that AL

OneWithWood · « **Reply #20 on:** September 07, 2011, 06:27:22 PM »

Talked to the dealer today. He had a conversation with the Stihl rep who said ripping logs is a common use for the MS660. As a matter of fact he had just donated the use of one to the Indiana DNR who were using the same mill to make beams for a bridge in Brown Co. State Park. The fact that I was using factory ripping chain was a plus for me.
Stihl sent two piston/carb kits to the dealer at no charge. The dealer is going to rebuild each saw and give me one at no charge. There is a reason I buy Stihl equipment. When the saw is ready the Stihl Rep wants to come out and observe.
I hope to learn a lot from that visit...

Kevin · « **Reply #21 on:** September 08, 2011, 10:31:36 AM »

I use 40:1 and have put a few tanks of fuel through a new saw before trying to mill with it.
The summer heat, air cooled engines and milling are a bad combination.

joe_indi · « **Reply #22 on:** September 08, 2011, 11:16:24 AM »

I have found that in a new saw 2 stroke oil at the ratio 25:1 for the first couple of tankfuls of fuel of running helps in running in the parts safely.
After that 30:1, 40:1 or 50:1, depending on the load.

Like many others have suggested, running a bit rich would be safer.
But the MS660 9for that matter all new Stihl saws come with the H screw opened to its stop on a carb with limiters or 1 turn out on ones without limiters.
So, unless it has been re-adjusted, the H is at rich from the factory.

Joe

ladylake · « **Reply #23 on:** September 10, 2011, 08:23:11 AM »

It's not the oil, 40:1 is fine, it's a too lean high setting that burns them up and a lot of new saws come set to lean thanks to the EPA. Steve

acco1840 · « **Reply #24 on:** September 10, 2011, 11:19:22 PM »

Ask your Stihl dealer if they can do you a deal on an Imported 090. I know they are still available to order here in Australia (although I had to buy it with a 36 inch alaskan mill to be able to get it). I have 2 090's on 36 inch mills running Stihl oil at 25 to 1 and have never had any trouble with either. As others have also said, Ethanol is from Satan and must be avoided. I had a 660 die in 12 months just from cutting firewood and dont think they are as good as they used to be. However, you seem to have a good dealer (I didnt), So I went back to the 090's. Aslso have old 070 I just put a rebuild kit through as a firewood/falling saw and love it.

w8ye · « **Reply #25 on:** September 11, 2011, 09:09:23 AM »

SETTING THE HS NEEDLE

I prefer to have the mixture set to where the engine is just on the two stroke mode in the cut. If the needle limiter gets in my way, I remove it!

Before engaging the saw chain into the wood, the saw will four stroke or make a flutter sound.

Try a few cuts and get the mixture set to where the engine is just on the edge of smoothing out when the chainsaw is fully engaged in cutting. If you slack up on the cutting pressure the least bit, the saw will go back into four stroke. As you apply cutting pressure, the smoothness of two stroking will return.

This extra fuel helps to keep the engine cooler so you do not overheat the saw and gall the piston on the exhaust side.

This needle setting will need to be changed for different types of wood, like the difference in white pine and rock maple or bucking and milling, milling chain or chisel chain. I keep my magic screw driver in my pocket at all times.

First find out where the needle is set? How far from closed is it? Open it up some and run the saw to find out what I'm talking about - Two stroke, Four stroke. Do not confuse the flutter sound of four stroking with the flutter sound of the ignition rpm limiter. To open the needle, you turn it counter clockwise. The High Speed needle is the one closest to the air filter.

OneWithWood · « **Reply #26 on:** September 11, 2011, 07:05:10 PM »

Well Stihl came through! They sent the dealer two piston/cylinder sets to repair the saws. The dealer rebuilt the saws at no charge. I picked up one Friday and spent today cutting up firewood to break it in.
The first thing I checked was the High speed mixture screw - it had been turned all the way out to the stop so I left it there. The idle was dropped to 12,800rpm. I mixed up some fuel to about 32:1 for the break in. I was only able to go through two tanks of fuel today. I will run another couple of tanks through it before I commence to milling. For firewood cutting I am running a 25" bar with RMC chain. The saw sings with this combo. For milling I have two setups now. I need to complete halving the 42" red oak log that I got 3/4 the way halved. I will then cut the halves into quarters. For that log I will use a 32" bar with 10° ripping chain. I also bought an updated Grandberg Mini Mill which has a better system for clamping to the bar that should allow for ripping without struggling to keep the saw near vertical. For the remaining large oak logs I am planning to use an Alaska mill setup with a 38" bar and ripping chain to slab the logs down to 22" x 28" cants running the saw horizontally and not buried in the log. The remaining logs have a number of limbs and knots so the end product will be 2"x 8" boards sawn through and through. The first log is clear and the goal is to quarter saw it.
It will be Tuesday or Wednesday before I can get to the milling. I will let you all know how it turns out.
Thank-you for the good advice.

I cannot say enough for the way Stihl and the dealer (Martinsville Ace Hardware) have worked with me on this issue. The dealer also sold me a new Stihl piston/cylinder set for my MS460 at a discount. I rebuilt the MS460 and put a big bore kit (52mm) on my old MS440 that I toasted a year ago after dropping a tree on it. The dealer is going to leak test the 440 for me to insure the seals are stil intact. So if this all works out I will have the new 660, my trusty 441, the 460 and the 440 with a big bore kit. That should keep me going for a while

Brucer · « **Reply #27 on:** September 12, 2011, 12:31:50 AM »

Quote from: Al_Smith on September 07, 2011, 08:13:53 AM

However if you are ripping ,milling whatever keep in mind that aside from stumping this is about a demanding of a task ever placed on a chainsaw .As such you have to run a rich carb setting .Lean fuel mix will run much hotter than rich .Too lean or even with a normal setting for average usage will not work out well on long rip cuts .

Sorry I'm late on this one. I just got back on line after a week with no FF fix.

You absolutely do need that rich setting on the carb. I wore out a 70 cc Jonsereds powering an Alaskan mill, but it took me 20 years to do it

. First thing I did after I got the Alaskan mill was set the high speed jet rich.

Quote

Then too in my opinion for the two cents it's worth seems to me that many have the bright idea they must cut lumber as smooth as if were ran through a table saw with a hollow ground cabinet blade so they use rip chain .Rip chains are slow,they pull saw dust instead of chips .To me they put undo stress on the saw where a standard old chisel will cut smooth enough for the purpose .After all if it is finish lumber it will be planed anyway .

Full comp conventional chain. File it straight across and hold the file level (a chain grinder helps a lot for shaping the chain to start). File it quite a bit deeper than you would for a regular cross-cut chain (tooth angle is about 45 degrees instead of 85 or 90 degrees). Use kerf wedges behind the saw to keep the kerf from closing onto the returning chain. Cut yourself a round of wood to sit on the outboard end of the handle and counterbalance the head (14" dia, 8" thick, with a notch to fit over the handle).

Do all this and feed the saw smoothly and you will see wood that's smoother than you'll get from a bandmill.

joe_indi · « **Reply #28 on:** September 12, 2011, 02:21:59 AM »

Quote from: OneWithWood on September 11, 2011, 07:05:10 PM

The first thing I checked was the High speed mixture screw - it had been turned all the way out to the stop so I left it there.

When you mention this it looks like the saws are running WJ-69B carbs with limiter caps. These carbs unlike the WJ-67A (without limiter caps) are lean burners to meet your EPA norms.
They have fixed jets of 0.62 size instead of the more generous 0.64 jets of the WJ-67A.
The limiter caps dont allow a richer setting unless you want to pull out the limiter caps.
The option is to leave the H screw out to its stop to avoid overheating when you are milling.
In addition you could try and replace the fixed jets with the 0.64 (part #1122 121 5604)
This will help reduce the heat.
But if changing the jet is not possible, the next option would be to change the cylinder gasket. In all probability what is fitted now could be the thinner 0.5mm.
The thicker 1.0mm gasket (part #1122 029 2306) should reduce the compression slightly so that the present lean burn jet will not have too much of an adverse effect.

Whether your dealer will agree to all this, I dont know.

Joe

woodzy88 · « **Reply #29 on:** September 12, 2011, 03:45:09 AM »

I've had saws do the same in big cuts when under load for to long . Seems to be worse if the logs are dry and produce fine dust.

ladylake · « **Reply #30 on:** September 12, 2011, 05:49:03 AM »

Quote from: OneWithWood on September 11, 2011, 07:05:10 PM

Well Stihl came through! They sent the dealer two piston/cylinder sets to repair the saws. The dealer rebuilt the saws at no charge. I picked up one Friday and spent today cutting up firewood to break it in.
The first thing I checked was the High speed mixture screw - it had been turned all the way out to the stop so I left it there. The idle was dropped to 12,800rpm. I mixed up some fuel to about 32:1 for the break in. I was only able to go through two tanks of fuel today. I will run another couple of tanks through it before I commence to milling. For firewood cutting I am running a 25" bar with RMC chain. The saw sings with this combo. For milling I have two setups now. I need to complete halving the 42" red oak log that I got 3/4 the way halved. I will then cut the halves into quarters. For that log I will use a 32" bar with 10° ripping chain. I also bought an updated Grandberg Mini Mill which has a better system for clamping to the bar that should allow for ripping without struggling to keep the saw near vertical. For the remaining large oak logs I am planning to use an Alaska mill setup with a 38" bar and ripping chain to slab the logs down to 22" x 28" cants running the saw horizontally and not buried in the log. The remaining logs have a number of limbs and knots so the end product will be 2"x 8" boards sawn through and through. The first log is clear and the goal is to quarter saw it.
It will be Tuesday or Wednesday before I can get to the milling. I will let you all know how it turns out.
Thank-you for the good advice.

I cannot say enough for the way Stihl and the dealer (Martinsville Ace Hardware) have worked with me on this issue. The dealer also sold me a new Stihl piston/cylinder set for my MS460 at a discount. I rebuilt the MS460 and put a big bore kit (52mm) on my old MS440 that I toasted a year ago after dropping a tree on it. The dealer is going to leak test the 440 for me to insure the seals are stil intact. So if this all works out I will have the new 660, my trusty 441, the 460 and the 440 with a big bore kit. That should keep me going for a while

12800 RPM doesn't sound bad but may need to be lower for milling, I'd pull those stops and make sure they are getting enough gas, as w8ye said four stroking as soon as you take some pressure off the saw.. Steve

Al_Smith · « **Reply #31 on:** September 12, 2011, 06:54:49 AM »

Quote from: Brucer on September 12, 2011, 12:31:50 AM

Sorry I'm late on this one. I just got back on line after a week with no FF fix.

.
Full comp conventional chain. File it straight across and hold the file level (a chain grinder helps a lot for shaping the chain to start). File it quite a bit deeper than you would for a regular cross-cut chain Do all this and feed the saw smoothly and you will see wood that's smoother than you'll get from a bandmill.

I've tried it that way plus basically turning it into planer chain by cutting the top plate off and just using alternate sides with a top plate filed straight across every third cutter to act as a racker tooth .Oh it cut smooth allright but slow as a snail .I was using a 125 Mac so there was plenty of power .I've had the best luck just using regular round chisel .

As I've said before in my opinion chainsaw milling is just an option as opposed to a bandsaw .Usefull at times but not the best way to salvage lumber from logs that otherwise would become firewood .

OneWithWood · « **Reply #32 on:** September 14, 2011, 12:58:03 PM »

Today I put the tach on the saw and got the high rpms to settle around 13500. I could not replicate the 12800 the dealer set it at. I ran a couple rich mixes through the saw cutting firewood the past few days but I went back to the 50:1 after having a conversation with the dealer. He pointed out that the unburned oil has to go somewhere which usually means something is going to clog up. There was an obvous film of oil around the decomp valve.
End result: I attached the new mini mill to the bar and proceeded to rip the log. I kept the saw just below wide open and it cut clean and relatively quickly. The saw never bogged down or seemed to heat up. Mission accomplished

Here is what was different from the other two attempts:
Updated mini mill gripped the bar securely and there was no slipping so I put a lot less pressure on the saw in the cut.
The temp today is in the mid sixties with a light rain - much better than 105°

welderskelter · « **Reply #33 on:** September 17, 2011, 07:07:10 PM »

I cooked my 066 just cutting firewood. I found out threw the forum that you need to modify the muffler. Drill a hole in it about 1/2 in, You get about a fourth more power to. Thanks Harold

ladylake · « **Reply #34 on:** September 18, 2011, 09:11:13 AM »

Quote from: OneWithWood on September 14, 2011, 12:58:03 PM

Today I put the tach on the saw and got the high rpms to settle around 13500. I could not replicate the 12800 the dealer set it at. I ran a couple rich mixes through the saw cutting firewood the past few days but I went back to the 50:1 after having a conversation with the dealer. He pointed out that the unburned oil has to go somewhere which usually means something is going to clog up. There was an obvous film of oil around the decomp valve.
End result: I attached the new mini mill to the bar and proceeded to rip the log. I kept the saw just below wide open and it cut clean and relatively quickly. The saw never bogged down or seemed to heat up. Mission accomplished

Here is what was different from the other two attempts:
Updated mini mill gripped the bar securely and there was no slipping so I put a lot less pressure on the saw in the cut.
The temp today is in the mid sixties with a light rain - much better than 105°

[/quote

If you cant get less than 13500 RPM you need too pull the limiter caps and get it lower for milling, soon as you push it some the same thing will happen. Steve

w8ye · « **Reply #35 on:** September 18, 2011, 11:17:59 AM »

Quote from: welderskelter on September 17, 2011, 07:07:10 PM

I cooked my 066 just cutting firewood. I found out threw the forum that you need to modify the muffler. Drill a hole in it about 1/2 in, You get about a fourth more power to. Thanks Harold

If you open up your muffler, there will definitely be a need to open up the mixture screws.

The reduced back pressure in the exhaust will cause the engine to run leaner unless you open the carb up to allow more fuel.

As was mentioned by Joe_indi, you may have to install a larger jet to get the carb rich enough?

Ax- man · « **Reply #36 on:** September 18, 2011, 02:18:45 PM »

Wow, It is threads like this that makes me glad that I am not using our good saws for milling and have turned to using my old 076 for milling . I have fianlly got ahold of TS 760 concrete saw air filter and have been able to get some good used cylinders and pistons plus rings just in case disaster strikes. I looked all over for these concrete saw parts and found a Sthil dealer right in my own backyard that had a bunch of those concrete saws and was more than happy to get rid of the carcusses.

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Author Topic: Cooked two MS660s in two days! (Read 8769 times)

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