Hey chainsaw Mechs/Specialists and Millers, I really need your help

[timberturner]

I'll try to recreate this as best as i can

I purchased a used Stihl 066 (the one they call the redeye) and was looking forward to using it to mill some fireplace mantles cuz i ran into a pile of cedar logs and an interested fireplace store owner...

put off ripping chain for the first day, went out , made a few ripping cuts/ about 5 feet long on a 12" diameter cedar log, (the log is fairly fresh and moist , if that makes any diff)

motor conked out on me about halfway through the 3rd cut, i took a break, let it cool, then fired it back up and tried to finish the job, and it conked out again...

I took it into the shop and they told me i had exhaust side piston scoring...

so, $222.00 in parts and 130.00 in labor later, i was back at it today and, to make a long story short..... I DID IT AGAIN !!!! ARRGGGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

i'm okay now... anyway, my mix was 50: 1, or 1 gallon + 1 of those little bottles of oil...

i was using wedges so as not to pinch the bar, air cleaner was clean... and i did my best to go at a slow rate of speed through the log, maintaining hi rev's.....

when i took off the muffler and examined the piston , my heart sank because i feel like such a saw killer/ i truly enjoy chainsaw milling and was looking forward to having a reliable saw...

with the new piston/cylynder kit, i felt i might have that , but now i know it is probably operator error, BUT I DON'T KNOW WHAT AND IT'S DRIVIN' ME CRAZY !!!

I'M IN MINNEAPOLIS AND IF THERE'S ANYONE ON THIS FORUM THAT'S INTO MILLING OR JUST A CHAINSAW GENIUS , I'D SURE LOVE TO HOOK UP WITH YOU (I PROMISE I WON'T EVEN TOUCH YOUR SAW)

HOPE ALL YOU GUYS ARE DOING WELL, I GUESS THAT'S ALL I CAN THINK OF... HOPE TO HEAR FROM YOU

TOM

 

[timberturner]

BTW, I USED RIP CHAIN TODAY

IN CASE ANYONE WAS WONDERING

 

[Fish]

Take the saw back and tell them you expect them to fix the
saw correctly this time. No extra charge.
When a saw comes in with a lean seizure, a certain problem
caused it. Replacing a cyl/piston assembly is useless unless
the original problem was rectified.
If the dealer is a Stihl dealer and refuses to help, let us know.
We can supply contacts with Stihl which should be of help.

 

[Gypo Logger]

Hi Tom, You should be running your saw at 32:1. Milling is very hard on a saw and creates lots of heat, If you do a muffler mod to your 066 it will have at least 30% more power if its one of the newer ones. It will also run 100 degrees cooler as well and last much longer too. For muffler mods do a search of 066 on this forum.
Gypo

 

[timberturner]

thanks

2 great pieces of advice, the mech is a stihl dealer

another distributor here said 50:1,, then i said i'll be milling , he said no, doesn't matter 50:1

i'll have to get more saavy with this to tell if the muff's been modified

my wife is going to be upset with this , so i'll have something good to tell her

thanks a million

 

[treeclimber165]

To inspect the muffler, use your Stihl torx wrench to remove the 2 or 4 screws at the corners of the muffler. Pull the front cover off. If you see a cage/basket in front of the exhaust port, that is the enemy. If you can see straight into the exhaust port and into the cylinder, you have an older model made before EPA screwed up our saws.

 

[tundraotto]

I would be suspecting an airleak in your saw or a new husky replacement that can take the milling

 

[jsikkema1]

cooling air

Make sure that you don't have any air cooling passages fillied up with wood chips... The starter cover will suck in those chips and being horizontal will pack in and restrict the air flow... Just did a 3120 for a guy that the starter cover was so packed with $hit that its no wonder the guy literally cooked it...

Jeff

 

[JimL]

Seen shops take and put in just a new piston an rings before, leaving old jugg on with some clean up and charge ya for a new kit....

 

[oakman]

all of the above is good advice, cept the husky one. you wanna cut wood, not vacuum up the forest! (just kidding). ask the tech who worked on the saw if he pressure tested the crankcase after the rebuild. this will show any air leaks, which will cause the saw to run lean. worn crank seals are a common thing in older saws, even some new ones get a bad seal occasionally. also, i agree with gypo, you need a bit more oil in the mix for milling. i run mine at 40:1. more than that is ok, but you can expect some carbon build up. also when you get the saw running good, you should adjust the carb so it isn't screaming lean with no load on it. more rpm's does not equal more power. when i am milling, i start out with the saw running 4-cycle rich, and i gradually lean it out till it will just break into two-cycle when you are in the cut and milling. this will assure you the saw is getting plenty of fuel, which will make the most horsepower, and keep it cool. remember, a two-stroke motor is primarily cooled by the fuel-air mixture. the air cooling provided by the fan is secondary. too lean, especially under heavy load equals low power, high temperatures, and melted aluminum.

 

[jokers]

Fish Is Right!!!

Hey Timberturner, Fish is absolutely right about going back and respectfully INSISTING that the guy who "repaired" your saw the first time fix it right this time, free of charge for the top end kit, and that includes finding and fixing what caused it to lean sieze the first and SECOND time! It should also be done quickly since you already endured downtime to get it fixed by this guy! You should expect to pay for the additional repairs that he did not do the first time but unless it`s something like crank seals it shouldn`t be too much. I know that you must be feeling pretty down in the dumps about this right now, but it is not very likely that you caused the second siezure by your actions so quickly after having it repaired the first time. This guy sold you a bill of goods and you need to hold him accountable.

Gypo has a good point about a fatter fuel/oil ratio. I would consider milling to be extreme duty over the long run, and the extra oil will be to your benefit. Most of the OEMs recommend 50:1 or 40:1, but they are dealing with the emissions aspect more than they are dealing with longer term reliability in my opinion. They`ve got their piper they must pay, but it`s up to the consumers to protect their own best interests. With the new clean burning oils, 32:1 is good. If your saw has an adjustable carb you should also run it just on the rich side of max rpm and as Brian said, open up that muffler. Russ

 

[stihltech]

lean seize

I would look for a reason it is running too lean rather than a richer fuel mix. It is possible that the hi side may have to be opened up a bit for this application, altough I have had to adjust some before they go out the door.
Yes, the tech should have found the reason for the failure, I am betting on an air leak or just to lean on the hi side.

 

[Dennis]

I have to agree...the dealer should have found the reason for the lean seizure...and myself as a dealer...would feel responsible for the second seizure...

the very first thing I do when I see a lean seize, is check the high speed jet...too many people like to hear the saw scream, and dont understand what they are doing...but, when that is not the problem....

-I will put my money on the intake boot or oiler side seal leaking...

 

[eyolf]

I'm going to side with those fine fellows who suggest you take your chain saw back to the shop that has NOT provided good service.

I take you to have said that you provided them with enough info as to how you choose to use the saw. An experienced, honest saw shop would have checked if the seals were leaking, would have inspected the rest of the unit thoroughly, and given you a report. If they found a lot of crud build up, a choked muffler, etc. they should have gently chided you about owner maintenance, and offered a maintenace tip or two. They should have conferred with you regarding your usage, and offered advice, or admitted they aren't familiar with your application.

Sounds like they serviced your saw (halfway?) and handed you the bill. Give them the opportunity to complete the job.

Your continued support, the kind of customer that shows up and asks for repair work and doesn't have a fit when it's time to dig out the wallet, are what keeps most dealers in business. Remind them that.

 

[timberwolf]

Hi Tom,

Sorry to hear of the saw problems. Sounds like a lot of good advice has been put forth. I was wondering on what bar length your using? I have noticed that I get a lot more heat and load on the saw with a longer bar, So I use a shorter bar where I can.

Talking to the Stihl shop before I bought my saw they sugested mixing on the rich side of 40:1 especialy for milling or hard service, I have done so and no problems yet (knock on wood).

I havn't opened up the muffler yet but I think I will, it sound like win win. If/When I do I'm going to try to borrow a thermo sensor to measure head temp before and after the modification atempting to maintaing a controled enviroment for the test. If I get anything of interest I will post the results.

I would imagine that a tuned pipe would be ideal for milling both to get the heat and exaust away from the saw and your face as well as to improve preformance.

Hope you get some good luck with repairs.

Timberwolf

 

[timberwolf]

One thing forgot to mention with opening up the muffler is the jet settings for mixture will need to be adjusted, more air means more fuel is needed to maintain air:fuel/oil ratio and reduced back presure may also have effects on fuel:air. But there is more detail if you search the forum.

Timberwolf

 

[Gypo Logger]

Hi there, I think I know why saws get fried once in awhile.
Lets say we are running a 32:1 or 50:1 mix of petroleum based oil for extended periods of time. Add to that a rich setting on the carb. In essence, what was 32:1 really is something like 20:1, cause of incomplete combustion due to a rich mix.
So what we are createing is a carbon buildup in the exhaust side.
Now lets take this same saw and set the carb to factory specs. So instead of the saw running at 10,000 rpm say, we have it running at 12,500.
Whats gonna happen? You got it, the increased heat and restriction cause the carbon to get red hot and ends up scoring the exhaust side. So the moral of the story is a saw should always be run at max factory rpm., with no half throttle stuff.
Gypo

 

[jokers]

I hope you guys aren`t taking what I said as "compensate for a lean sieze by changing the fuel/oil ratio" or to run the saw rich. The cause of the improper fuel/air ratio needs to be found. I was suggesting that under extreme operating conditions, a saw running a numerically lower fuel/oil ratio, wide a$$ open, with the high speed adjusted just slightly rich, 50 or maybe 100 rpms below factory max, would be better lubricated and cooled. It`s imperative that anyone running a saw for milling learn to read the saw`s performance and watch for reaction to variables, known and unknown. In other words, you have to continually monitor performance. I also strongly believe in checking the sparkplug regularly enough to know if you are running too rich, it`s an easy enough thing to do and it has worked for me. I believe that if I am to err at all on the fuel/air ratio, I`d be best off to err on the side of SLIGHTLY rich. Russ

 

[eyolf]

John, that sounds pretty good, and I'm certain that more than a fews piston have been scored that way.

I spent 3 years as parts and service guy for a regional outdoor equipment distributor...we had 5 states' distribution rights for Jacobsen lawn mowers, and I imagine at least a few will remember the old Jake 321/501 two-stroke lawnmower engine. The second most common cause of failure of this engine (first was straight gas) was carbon build-up. This was the primary reason Jake went to 50:1 in the "70's. Carbon can glow red and cause pre-ignition and extreme heat, or chunks break loose and get stuck in your motor. There were explicit instructions for keeping the cylinder fins clean, and removing the muffler to clean out carbon.


But that doesn't excuse the errant Stihl shop...our would-be sawyer friend explained that he was sold a new top-end. New top end has no carbon build up, and muffler should have been inspected and serviced if required.

 

[bwalker]

my $.02

For optimum engine life when milling I would run a good high temperature ester synthetic oil at at LEAST a 32:1 ratio. Maxima k2, Motul 800 when used at these ratios will protect the motor very well and will leave alot less residue than the factory petroleum mix oils at 50:1. It also would not hurt to back of the hs jet a bit as other have mentioned.