Problems with Stihl 066m

[dbarbee@bellsou]

I hoping you guys might be able to give me some direction on what to do with this saw. The saw is a stihl 066m. I was cutting up a downed tree and while sawing at near full rpms the saw locked up. Checked the fuel and there was oil in the gas. I let the saw cool down then i put some two cycle oil in the spark plug hole to lubricate the cylinder and hopefully reduce any damage. I turned the motor in reverse and freed the motor. I drained all the oil i cold out of the spark plug hole. The motor seems to turn fine now. But I can not get the engine to fire. I put a new plug in and checked to make sure it was firing. After trying to start the motor several times i pulled the plug out and you couldn't tell it has burnt anything. The saw is blowing fuel out the compression relief valve the the motor doesn't fire. I'm not really knowledgeable about the internal workings of these motors. It just doesn't make any sense to me. Is the motor fried, you think? Anything else i need to check? Any advice would be greatly appreciated.

David

 

[sILlogger]

package it up and send it to me...ill give u a good price for it have u checked for spark? pull the plug out and with it plugged into the wire ground it out and pull it over to see if it sparks

 

[ShoerFast]

Welcome to the site David

When you say it locked up,,,,, do you mean that it just quit? or locked up and would not turn over by the rope?

First place to look for engine damage is by pulling the muffler

It was mentioned how to check for spark.

But a better idea, just package that saw up, and I will top the offer by that other guy!

 

[sILlogger]

dbarbee, your my neighbor, i live over in carbondale, IL. only 70 miles away. small world. are u a logger, or an occasional chainsaw user. is it a newer or older model 066? i hope u get it figured out. if it stopped suddenly, as in came to a screaching halt i would definitely pull the muffler and look at it. or send it to me, i'll send a check and get it out of your hair keep us posted on what u see as you get into it and u will get all the help u can handle. welcome to the site btw

 

[dbarbee@bellsou]

The saw does have spark. I have haven't pulled the muffler yet. Took a small peak through the spark plug hole, didn't see any shavings or anything. When i saw the saw locked up, the motor wouldn't turn. I had to turn the motor backwards by hand to free it up. Since it locked up the motor hasn't even tried to start. The saw was bought about 6 years ago or so. My main line of work is woodworking. I have a woodmizer sawmill and use the saw only for cutting logs to size. Really the saw never saw that much use. It had always run perfect, well, right up until it locked up. If the motor is unfixable, I was just trying to figure that out before taking it to somone who would charge $50 dollars for that news. If I do need a new motor does anyone know how much that would cost or a supplier? I appreciate all the offers to take it off my hands but if its cost effective to repair i would just assume give that a shot.

 

[ShoerFast]

From the hip,

You may find that your going to need a cylinder - piston, Baileys , a site sponsor has them for $120 -

http://store.baileys-online.com/cgi-bin/baileys/5638?mv_session_id=68tBaw6t&product_sku=CK 066

They also offer a Big-Bore kit for that saw, but last I have heard is that it has been placed on the back burner.

Remove the front handle (4-screws) the top plastic, and the cylinder (4 Torex head screws) and your there. checking the crank rod and bearings, but if it just needs a top-end , it would be hard to spend an hour at it.

Mic the wrist-pin, if there the same (no excessive ware on the original,) use the original wrist-pin,,,,, a lot lighter.

Edit: should mention find the reason it siezed, crank seal, tore loos inlet boot, lean fuel delivery,,,,

 

[sILlogger]

i agree with shoerfast on that one, find out what caused the lockup problem before throwing on a top end. keep us updated on what u find. good luck

 

[dbarbee@bellsou]

I saw that a recent bailey's catalog i have here at the house. Is this a repair that a layman could pull off or do I just need to take this to a professional? Done alot of maintenance but never overhauled a motor like this before. Thanks...

 

[sILlogger]

if u can follow directions u can pull it off,4 torx bolts for the top cover, pull spark plug, loosen and remove intake boot from cylinder. take off 4 cylnder bolts out remove cylinder. pretty much the jist of it. if i was you i would buy the Wiha T27 torx wrench and the piston ring compressor from baileys while your at it, go to your nearest stihl dealer and get the $3 base gasket, skinnier of the 2,( i think .5mm.) put it on install new cylinder, minor carb adjustments.

then there is always the concept of ship it off, pay 3-400 and have it woods ported AND get a new piston an cylinder, and have a bad azz saw that will be alot of fun!! which is what is going to happen with my 066 soon.

 

[ShoerFast]

I saw that a recent bailey's catalog i have here at the house. Is this a repair that a layman could pull off or do I just need to take this to a professional? Done alot of maintenance but never overhauled a motor like this before. Thanks...

Take it one step at a time,,,

It is really a straight forward replacement, once you find the reason it seized.

You may find out more once it is apart, but just plan on double checking/ replacing the fuel-line, filter, impulse hose, double check the inlet-boot and check the crank seals,,,,, or just plain replace them. Might as well OH the carb also. set the cylinder on a new gasket and your really covered.
It's just me, but I don't like to toss parts at something in hope I fix something, knowing whet seized it would give you a lot of comfort!



Pay real close attention to how it runs at first, keeping it close to a good 4-cycle burble for a few tanks.

Something will happen while you run your first rebuild, there are no words for it, but you will know what I mean when it happens

Push come to shove, there are sponsors here that would take that saw as a basket full of parts and send it back fixed or a hot-rod (modded / ported) saw, Dean at Washington Hot Saws is one of them.

 

[dbarbee@bellsou]

Update with pic

Heres what I found when I pulled the muffler.

You see how chewed up the piston is. The damage seems to be only the the muffler side of the motor? Assuming this is because of the heat on the exhaust side. The cylinder wall seems to be in great shape on the intake side. You can still see the milling marks in the cylinder walls. Wouldn't that lead you to believe heat was what caused the motor to seize, rather than mechanical reasons? If thats the case what would cause the motor to run so hard that it overheated? The only thing I could think of was lack of oil in the gas mix, but like I said I checked that. I'm pretty careful about that. I use the Stihl oil that has already been premeasured.

After seeing the damage I was going to go ahead pull the top of the motor off but i ran into a problem. How the h*ll you supposed to get those 4 torx screws out? :help:

 

[sILlogger]

a long handles T27 torx, or the L-wrench that usually comes with a stihl weedeater, u could prolly to buy a T handle wrench at walmart or a hardware store, or baileys has them

 

[ShoerFast]

The exhaust side is also the thrust side, the piston has more of a side load firing then dose the compression side or intake side.

Just from what your pix is showing, pull the jug and get a better look, if there is metal missing from the cylinder, it may be time for a new cylinder.

A good picture from the inside and maybe it will be a little more clear on why it seized?

Dose this saw have a lot of hours on it?

 

[dbarbee@bellsou]

I would say they saw has less than 20 hours on it. Its used seasonally to cut logs to length for my sawmill. I don't use my sawmill commercially, just to provide me with lumber. This saw has never been used commercially. Maybe that is some of the problem, lack of use may have let a seal dry out. I stopped in and talked to a repair guy today and he explained a little about what you guys have been telling me. He said he thought it was definitely from an air leak. He told me that if I would get the parts to rebuild it he would put the kit in for approx $110. That was for labor on the cylinder kit and crank seals. Still debating. Would love to take top of the motor off to talk a look but those exaust side torx screws in an awful spot. Still haven't been able to get those out.

 

[sILlogger]

if u have a long handles torx u can go down through the holes in the cylinder fins and get to the cylinder bolts. 20 Hours!!!! that sure isnt' very many........hummm.....do u clean the airfilter pretty often?? u might be surprised how salvageable a cylinder is, atleast i was when i started working on saws. a good honing will go a long way. u might be able to get by with a $50 cylinder, but still too early to tell

 

[ShoerFast]

Should be able to pass the Torex all the way down from the top via holes in the cylinder fins?

If your repair guy can pressure / vac test it, you will know much more.

Very low hours, you may be able to replace the piston, if the cylinder trues up.

 

[dbarbee@bellsou]

Here's the damage...

One thing that still bugging me though, would this cause the saw not to fire? Seems like it would start but just not have as much compression. The gasket seemed to be good shape also, no visable damage or evidence of it leaking.

I'm not sure what I'm looking for, when we talk about the crank shaft seals. I understand what your talking about, but do I have to tear down more of the saw to find/replace them? So far this seems pretty straight forward and I can probably put the cylinder kit in myself, h*ll I have already done the tear-down. I took a look at the intake hose and it looked to be pretty good. Didn't see and cracks or anything, the rubber seems to still be pliable. The clamp was on it tight also. Any recommendations are welcome (i gotta learn some how, us poor folks gotta learn to do for ourselves! )

Oh yeah, one more quick question. If I do buy the rebuild kit from bailey's, will it have the compression relief valve in it or do I have to buy that also and put it on? Wasn't obvious how that thing went on or come off.

 

[sILlogger]

ouch!!! that is painful to see! as for the firing question....i suppose it could have sheared the flywheel key on the sudden stop, not sure, but anything is possible...that could have caused the saw not to fire.....the cylinder looks rough..but it might true up once a hone has been taken to it, if the coating isn't completely ate through(can't tell)...only one way to find out... personally im not thinking that it was the crank seals. but thats just me...was the saw running lean??? had the air filter been cleaned??? just a few ideas

 

[sILlogger]

as for the compression release you'll have to take the old one off off your cylinder. remove the rubber grommet from the top and i think it takes something like a 1/2" socket to get it off and it treads out of the cylinder. baileys does have some that will fit the cylinder, but they are blue button husky style ones.

 

[dbarbee@bellsou]

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?