Super XL Automatic seized up

[Robert Garcia]

Went to cut some wood and like a numbskull added fuel mixture without shaking it to mix. Made it through a log bigger than my thigh and while cutting it the saw stalled out a couple of times. I was puzzled it had not stopped like that before but restarted and I finished that cut and put another split piece of wood to cut and it stopped and would not pull totally seized. I thought about it and realized what I had done.

I removed the coil start assembly and it was free, it was not my problem. Removed bar and chain then the exhaust muffler to look at the piston. Fresh scoring on piston. Damn. So I pulled the spark plug and filled the exhaust port with Marvel Mystery Oil. Gonna let it soak overnight for what it's worth.

I'm wondering what side is good to put a wrench or socket to to try to break the piston loose? If I remove the clutch is the crankshaft on that side a good place to latch on to? Or is the flywheel side of the crankshaft the place to try? Any of you been there, done that? Thanks, looking for direction this was a find at the dump and had been left out in the weather. Chain rusted, the owner said he just wanted it out of his garage and so he threw it away. I grabbed it and cleaned it up. I joined this site at that time and read about pulling the muffler and looking at the piston and cylinder to get an idea of any problems. It looked great at that time and it has worked great until I screwed it up last Saturday. Pics of what it looked like when I got it.

 

[a. palmer jr.]

Looks like the previous owner took great care of it!

 

[Robert Garcia]

Looks like the previous owner took great care of it!

You can see why the less mechanically inclined might toss it! But I've no room to talk damaging it the way I did.

 

[a. palmer jr.]

With enough patience it can come back to life like new!

 

[Brushwacker]

Ya, been there, straight gassed 2 different 034 supers locked them up tight, once over heated an old xl 12 locked it up tight. Don't remember what i used for lubricants, i am sure it was more then 1 and may be a combination. Seems like i started with wd 40 and then added a little motor oil or 2 cycle last time. Just take the starter cover off and rock the flywheel back and forth worked for me on all 3. The pistons all looked a bit scored but they all worked fine for the remainder of the time i had them and i sold the first 2 in good working condition years later about 7 on the 1st 034 and i am about 3 or so on the 2nd 034 now. Seems like it takes an extra pull to start it since, power feels close to original.

 

[Yukon Stihl]

It wasn't your gas,it takes forever for oil to settle out of gas.
You should pressure vac test it before you tear it apart.
I have lots of parts saws if you need parts

 

[Okie]

It wasn't your gas,it takes forever for oil to settle out of gas.
You should pressure vac test it before you tear it apart.
I have lots of parts saws if you need parts

Right: Most likely the saw was running lean and You never did notice such when doing just lighter cuts where the engine was not loaded up for a long time. If the saw idled good then the lean condition is most likely due to the carb being adjusted incorrectly (too lean) and when the engine is into a long cut and really loaded up the piston starts getting hot and swelling into the cylinder wall then this friction heat goes into a runaway. If you are little bit lucky, try laying the engine on it's side with little bit of ATF added into the ex port and the spark plug hole.
After day or so try gently rocking the flywheel without breaking off any cooling fins. I've seen them free up on their own after about 8 hours of the piston cooling down and be useable for a very long time if the lean condition is cured before putting the saw back to hard use.
I've seen them free up and run a long time if the lean condition that caused it is repaired afterwards.
The way I confirm that a saw is not running lean (or getting too hot) and headed for a another sieze is to use a IR therometer. I first try to adjust the carb by ear for 4 cycling. Then take the saw to a big downed log for a full bar cut with a sharpe chain so as the engine is loaded up really good and will cut with using just one hand to hold the saw and start monitoring the saws block temp at the jug and if the temp starts going to 350 fast the engine is running lean and if it's headed to 375-400 do not turn off the engine because the temp will keep rising, take it out of the cut and run a medium throttle letting it cool down then troubleshoot.
A chainsaw engine under full load in a cut will normally start heating slowly and hover around 350 degrees or less. Going to 350 fast is not good and most generally due to not enough fuel keeping the piston cool. (too much air)
Assuming all else is ok such as cooling fins not clogged, spark arrestor not clogged, etc.
Lots of guys use a tach only and a tach won't tell you if a saw is running lean and going to overheat. (because a saw that is running really lean in a full bar cut will overheat without exceeding the rated tachometer rpms)

You can find a IR therometer now days at a very reasonable price.

 

[Old2stroke]

Right: Most likely the saw was running lean and You never did notice such when doing just lighter cuts where the engine was not loaded up for a long time. If the saw idled good then the lean condition is most likely due to the carb being adjusted incorrectly (too lean) and when the engine is into a long cut and really loaded up the piston starts getting hot and swelling into the cylinder wall then this friction heat goes into a runaway. If you are little bit lucky, try laying the engine on it's side with little bit of ATF added into the ex port and the spark plug hole.
After day or so try gently rocking the flywheel without breaking off any cooling fins. I've seen them free up on their own after about 8 hours of the piston cooling down and be useable for a very long time if the lean condition is cured before putting the saw back to hard use.
I've seen them free up and run a long time if the lean condition that caused it is repaired afterwards.
The way I confirm that a saw is not running lean (or getting too hot) and headed for a another sieze is to use a IR therometer. I first try to adjust the carb by ear for 4 cycling. Then take the saw to a big downed log for a full bar cut with a sharpe chain so as the engine is loaded up really good and will cut with using just one hand to hold the saw and start monitoring the saws block temp at the jug and if the temp starts going to 350 fast the engine is running lean and if it's headed to 375-400 do not turn off the engine because the temp will keep rising, take it out of the cut and run a medium throttle letting it cool down then troubleshoot.
A chainsaw engine under full load in a cut will normally start heating slowly and hover around 350 degrees or less. Going to 350 fast is not good and most generally due to not enough fuel keeping the piston cool. (too much air)
Assuming all else is ok such as cooling fins not clogged, spark arrestor not clogged, etc.
Lots of guys use a tach only and a tach won't tell you if a saw is running lean and going to overheat. (because a saw that is running really lean in a full bar cut will overheat without exceeding the rated tachometer rpms)

You can find a IR therometer now days at a very reasonable price.

You bring up an excellent point! If the manufacturers would spend less time trying to make saws fool proof with autotune and do something serious to develop engine protection we would all benefit. A simple step would be to sense the cylinder head temp and interlock it with ignition so that if the temp got into the danger zone it would just shut the damn thing off. Back in the early days of snowmobile racing there was a thermocouple washer you could place under the spark plug and use it to monitor head temp, and that was a LONG time ago. Would be a simple thing to do today compared to autotune.

 

[Okie]

Oldstroke: Good point about sensing temp for shutdown.
Some 2 cycle outboard motor engines has/had such a warning.
A simple temp disc as you indicate would do the trick, but again the manu of chainsaws would be shooting themselves in the foot and not sell as many parts and saws.
One indicator of a chainsaw heading for seizure is if into a big log usually a full bar cut for an extended period of time and the engine rpms seems to be slowing down the longer the saw is in the cut and you remove some of the load or take it out of the cut and it starts increasing speed again for awhile it might be overheating. (You have to have a ear for such and pay attention to the saw talking to you)

 

[Robert Garcia]

Some rocking back and forth with a screw driver in the flywheel fins worked. No damage to fins. Gonna do some cleaning with it partially disassembled and when back together will adjust carb to slightly rich at full throttle and hope that will prevent this from happening again. I've been getting wood already split and a little long for my wood stove. So it has been some quick cutting. That log was the first big piece of wood I tried to cut with this so I think your guess is right on. Thank you all for your help!

 

[Okie]

Just couple hints to consider:
You might remove the muffler and look at the piston just to get an idea. If you have a good reliable small engine compression gauge you might check the compression of a non-oily cylinder. If it's less than 120, 100 minimum the saw is going to be weak. You cannot use just any compression gauge, especially automotive type will give a low false reading. If you don''t know for sure about a compression gauge check it on a good running saw or two to see if it will even give a high reading.

You can find a IR therometer very reasonably priced now days. I would use such to confirm the temp is not again overheating before putting the saw to good use. Constant overheating is not a good thing. Solid Signal and Amazon sometimes have good IR's with free shipping. ($25 or so)

You need to think about re-searching how to adjust a chainsaw carb (high speed jet turned out to (rich) as far as possible for 4 stroke out of the cut) so as the saw 4 strokes.

 

[Robert Garcia]

Just couple hints to consider:
You might remove the muffler and look at the piston just to get an idea. If you have a good reliable small engine compression gauge you might check the compression of a non-oily cylinder. If it's less than 120, 100 minimum the saw is going to be weak. You cannot use just any compression gauge, especially automotive type will give a low false reading. If you don''t know for sure about a compression gauge check it on a good running saw or two to see if it will even give a high reading.

You can find a IR therometer very reasonably priced now days. I would use such to confirm the temp is not again overheating before putting the saw to good use. Constant overheating is not a good thing. Solid Signal and Amazon sometimes have good IR's with free shipping. ($25 or so)

You need to think about re-searching how to adjust a chainsaw carb (high speed jet turned out to (rich) as far as possible for 4 stroke out of the cut) so as the saw 4 strokes.

Thanks Okie!
Your first response on this thread in regards to my saw possibly running lean and your procedure to check for that condition mentions, and I quote, 'I first try to adjust the carb by ear for 4 cycling,' and I wanted to ask what you meant by that. Then again on this post I'm replying to, 'You need to think about re-searching how to adjust a chainsaw carb (high speed jet turned out to (rich) as far as possible for 4 stroke out of the cut) so as the saw 4 strokes.' These little jewels are two-stroke and so I'm puzzled. Would you care to explain to a newbie your meaning please? I include the page from Homlite on carb adjustment.

 

[a. palmer jr.]

I can't emphasize enough that saws should be kept clean! I have never overhauled or put a top end on a saw that was clean, they're usually filthy. I don't know why a person couldn't at least take an air hose and blow the saw off when he gets in from cutting.

 

[Robert Garcia]

I agree and am guilty of a dirty saw. I gave it a lick and a promise when I salvaged it out of the dump and it seemed to be fine for what I was doing with it. I did not do a total removal of all components but with the coil start off, and the bar and chain removed I started cleaning tonight with a pic, small screwdriver, wire, and some air and rag to get the sawdust and oil caked around the flywheel, coil, centrifugal clutch, and cooling fins of the jug. Again not immaculate, but much better! About two cups of gunk!

 

[a. palmer jr.]

I think it's that gunk, grease and sawdust that are responsible for at least some of these saws overheating. I think that's the main reason modern saws have the fuel tank toward the rear on the back handle because they got hot and boiled the fuel..

 

[Okie]

You asked:
so as the saw 4 strokes.' These little jewels are two-stroke and so I'm puzzled. Would you care to explain to a newbie your meaning please?

Search on-line and you will probably come up with a link back to this site about how a chainsaw sounds when it 4 strokes. (sounds similar to a 4 stroke engine) when the 2 cycle engine is unloaded at high speed indicating a over rich fuel condition. (some of the links will have video with sound)
Fuel (gas) over rich hitting the piston keeps the piston cooler. When the engine is loaded up the 4 stroke sound goes away.

It is very easy to adjust a chainsaw carb WRONG so as the engine screams (and rpms can be within rated specs) and really sounds great and cuts really fast and sounds powerful in a cut, but if it's running lean and into a very long cut, big log, full bar cut the engine will usually start overheating fast, piston swell and chew on itself and the cylinder wall.
Using the saw with the carb adjusted lean, overheating may not ever be noticed when taking lighter cuts on and off the throttle.

Some saws carbs do not four stroke sound very good and that is why I use a IR temp to check the actual block temp in a long full bar cut. I live in a rural area and keep a big log on the ground few yards from my shop for testing saws temp and chains after I hand file.