Problems with Stihl 066m

[Sprig]

The saw seemed to be running at high rpm's, guess to high. At the time I didn't realize that an air leak could cause this. The saw always seemed to 'scream' pretty good when you opened the throttle all the way up.

So you think the bailey's kit is way to go at this point? For some one who is pretty ignorant about this stuff?

How do I check this flywheel key? The motor wasn't even trying to fire. When I pull the plug out and place it on the motor and pull the string I do get spark. When I put the plug back in and attempt to start the motor I get nothing. There was fuel blowing out of the compression relief valve but the motor would never try and fire. Maybe I just had it flooded and it couldn't fire, but I don't think so (at least not when I started, I yanked on this thing for 30 minutes). Guess I could start by putting in the cylinder kit and work from there?

Obviously you are not still trying to start it, looks like you ate some rings there, probably hard to start because you had no (or very little) compression, more than likely a darned good thing it didn't fire up again too
Now why the heck was a motor-newb like me postin' here, oh ya, may it be an idea to check the crank & bearings while you are in there? Q actually, just wondering why it failed but also wht other damage it could have done if it did a dead stop thingy. Lots of very knowlegable folks here (and welcome), with a bit of patience and some sort of monkey wrenching exp. you should be able to get it back to its former self, but as the guys have said so many times, gots to find why it did that in the first place with so little time on it. Nother Q, would a leaned out mix/adjust do this sort of thing too? Just wondering again.

And have fun on the learning curve!

Serge

 

[dbarbee@bellsou]

Were on the same page, I'm just wondering if getting a new cylinder kit on it will be the quickest way to find out what the real problem is. When I get it started maybe I can have someone who knows more than me see if there is any issues with how its running. With some great advice from the guys on this forum I can at-least see what the problem is and hopefully get the ol' girl purring again. Tomorrow, I'll investigate some more.

 

[ShoerFast]

The saw seemed to be running at high rpm's, guess to high. At the time I didn't realize that an air leak could cause this. The saw always seemed to 'scream' pretty good when you opened the throttle all the way up.

So you think the bailey's kit is way to go at this point? For some one who is pretty ignorant about this stuff?

How do I check this flywheel key? The motor wasn't even trying to fire. When I pull the plug out and place it on the motor and pull the string I do get spark. When I put the plug back in and attempt to start the motor I get nothing. There was fuel blowing out of the compression relief valve but the motor would never try and fire. Maybe I just had it flooded and it couldn't fire, but I don't think so (at least not when I started, I yanked on this thing for 30 minutes). Guess I could start by putting in the cylinder kit and work from there?

Your flywheel key may be fine, but you are telling me a couple of things here, and the pictures,,, good pic!

That Saw seized from lean failure, but your telling me something here, that it was a screamer,,,, if you think it was running to fast, I think your right. Fast is too lean (to a point)

If it had a good idle, and started good cold, your still going to want to check everything, but I'm not as afraid of it,,,,, I think it may have been lean since new, if you have never checked it?

I just bought a new MS-361 , asked my dealer if I could hear it on his tach to get an idea,,,, and it was screaming at 17K, we cut the tabs off , it may not have made it 20 hours that lean?

If your saw was not set up right, or never adjusted right, 20 hours may be about right.

Do a couple searches if you would like, check on using acid to clean cylinders, hones in cylinders and on carb tuning and on how to cut the limiter caps-tabs off.

From what you said so far, if you put a cylinder and piston kit in it,,,, or a piston and rings if the cylinder trues up, it will start for you,,,,,, but your going to want to turn the "H" screw out to a full 1 1/4 - 1 1/2 turn to start with. maybe have someone walk you through setting the carb?

There would not be many here that would bet that not fatting the carb up, just starting it with a new cylinder and piston, that it would run well past 15K? It should be around 13K free speed.


Have fun!

 

[dbarbee@bellsou]

There would not be many here that would bet that not fatting the carb up, just starting it with a new cylinder and piston, that it would run well past 15K? It should be around 13K free speed.

Huh? I'm not up to speed on my chainsaw jargon. So If I got you right, I need to do the cylinder kit, make the adjustment on that mixture screw, get it started, have someone tune the carb correctly.

When I bought this saw this was the first stihl I had ever owned. Thought what it was doing must be normal. Guys at the shop where I bought it said it was tuned and ready to go. Guess by tuned they meant they took it out of the box. From what I understand from bailey's my saw had the incorrect sprocket on it also. Bailey's sent me a replacement for free, nice folks.

 

[tek9tim]

Well, at 20 hours, you shouldn't have a problem with an air leak, but perhaps you do, maybe you should have your case checked. Probably easiest to have a dealer do this for you. Odds are that you don't, but you could at least eliminate variables. You didn't happen to be at the end of your tank of gas, did you? I melted down the piston on an 046 trying to get 1 more little cut in.

Wrong sprocket? That's a matter of opinion most of the time. Unless it's the wrong pitch for the chain they sold you.

Edit to add: somebody mentioned cleaning the air filter... a dirty filter will richen up the mixture, thus reducing heat. Also, I know some loggers that'll go way more than 20 hours of hard cutting without cleaning their air filter. (not that I'm promoting such a practice, but it won't kill a saw that quickly)

 

[sILlogger]

here is what i think happened, based on what u have said and past experience. my guess is that the carb on the saw was not adjusted properly and has been running too lean since the saw was new. the saw was turning too high of rpms, starving for oil=scoring, piston got hot and swelled and locked up inside the cylinder=thus more scoring. that cylinder might be able to be cleaned up with a good honing, possibly, i'm running an 066 right now that had a pretty scored up cylinder that i cleaned up by honing. but if u want to remove all doubt buy a piston and cylinder kit. flush out the crankcase a few good times with premixed gas to get any metal particles out and install the piston and cylinder. some people are different but i use white lithium grease (assembly lube) on the cylinder walls and piston when putting them back together. once back together thread the H screw on the carb all the way in (clockwise) and back it out around 1 1/4 turns counterclockwise. just as well start with a new spark plug. and then start the saw. it should fire up for you. i'm guessing u don't have a tach and prolly dont' wanna tune by ear so i would take it to someone with a tach and have then tune it to around 12500-13000 rpms with a bar and chain.

chainsaw jargon
"screaming" not always good, in this case too my rum rums and saw was lean
"fatten' up the carb" turning up the fuel, or "richening" the saw to allow more fuel and lowering rpms.
"high speed come apart" what this saw did, and what i do on occation

Hope this helps!!

 

[sILlogger]

o yea, im gonna pull back on the sheared flywheel key idea, after looking at the cylinder the key prolly didn't shear. and when i was asking whether the air filter had been cleaned i didn't know if the saw had ingested something. personally i tap out my air filter about ever 3 tanks of fuel.

 

[dbarbee@bellsou]

I don't air cleaner was an issue. The filter was clean. I clean the pre-filter after every job or when i have to change/adjust the chain.

The sprocket issue probably is a matter of opinion. With this saw and the old sprocket it was VERY easy to get the chain so hot it would loose its temper. I' m not talking about a chain is dull as a butter knife. I'm talking about fresh chain. Bailey's precut loops wouldn't even fit on my saw. I talked with them for a while about the issue and they had me go out and check the sprocket. I don't remember how big it was but he said it was to big for a saw with this horsepower. They sent me a new sprocket and I didn't have trouble with the chains burning up anymore. They guy at bailey's said that sprocket was for a saw that is underpowered and needs to increase chain speed to overcome its lack of torque.

Probably didn't help that the saw was apparently running lean also.

I'm gonna talk it over with the little lady tonight and will probably go ahead and order the bailey's kit. Some one with more experience than myself could probably hone the current cylinder. The drags really aren't that deep. Alot of the worst looking places are actually where the metal from the piston soldered itself to the wall of the cylinder. I used to work at a factory that made pistons like these. If you let the die get to hot the same things happens to the die.

Is there any certain technique to remove these clips to free the piston? Haven't tried to remove the piston yet.

SILogger, can you recommend someone in our neck of the woods to tune this saw when I get it back together? And maybe check it for leaks?

 

[sILlogger]

Fb McAffoos in Benton IL is who i have do any service work that i need done. always had good luck with them. not sure how far that would be for ya, but they have always took good care of me

 

[oregonlumber]

i am new to this site, but have had the same problem with my 066 metal tab.
what fried my piston was that the clutch drum sproket and needle cage were to large and the carb was set a little on the lean side running about 14000 to 14500rpm. new piston, clutch drum,ect.. and i went ahead and changed out the bearings as well as crank seals and gasket. i couldnt see rebuilding top end, only to find that something in the bottom end going out and blowing it up again. now i have a old saw that runs like new.

 

[West Texas]

You can buy a long handle screw driver like torque's wrench at Sears, usually a 27 will do it. If its really tight, you can grip the handle of the wrench with a cresent wrench or a pair of pliers to break it loose, then screw it on out easily.

 

[dbarbee@bellsou]

Hey guys, is there a trick to getting those retaining rings (or whatever they are called) out of the piston assembly so I can remove the piston? Is there a special tool? Looked little tricky to remove them. Just thought I would ask before did something stupid trying to get them out.
:stupid:

 

[dbarbee@bellsou]

Got my rebuild kit today, any last hint tips or suggestions before I attempt to install this thing? The inside of the cylinder is already oiled down, is that enough lube to protect the motor at initial startup? Should the fuel have extra oil in it the first few tanks? Any help that would prevent me from screwing up here would be appreciated.

 

[dbarbee@bellsou]

Running at last, oh my god, running at last

First off...I would like to thank everyone for all their tip/hints/suggestions. I truly appreciated it. I went from being told I needed to buy a new saw (about $900) to fixing mine for $120 dollars. A true testament to your expertise, and patience. This kind of generosity is what the internet should be about, well, maybe a little **** too. If you ever find your way to Kentucky, the beers on me.

I couldn't wait for any more suggestions before I started. So i went out and give her a shot. Took me about 2 hours to put it all back together. The hardest part was getting that piston in the cylinder. I don't have a ring compressor so i had to make due. I did most of it twice because I was such a hurry I forgot to put the cylinder gasket back on first. So i had to take the cylinder and piston back off to put it on. Should be getting pretty good at it now. Anyway, after getting everything bolted back on I had to try and start her. She fired up on the second pull. Never expected that. This saw hasn't been started in about a year and a half. Never heard such a beautiful sound. I took special care that it didn't get rev'ed up to high. Just let her idle for a minute. Before using her I'm gonna take her to be tuned. Hopefully I can find someone locally who knows what they are doing.

 

[oregonlumber]

good i always like to here that an old saw has got new life. the only other thing that i would recommend is that you have the saw set to a low rpm and run 3 or more tanks of fuel through it and go through some chips!!

ya without the guy here on the arborist site i dont know if i would of gotten my old saw running again