Home Forums Hunting & Shooting Hunter's Campfire Stihl 025 giving me fits!

Matt,

Had the chance to "sleep on it" and had another thought:

Sometimes when a saw is stuck/pinched by the operator, they pull on it hard to free it. If this happened, the annular buffers (rubber mounts) are stressed and it is possible to pull on the impulse line responsible for pumping the carb. If the plug did not appear to be wet or the saw flooded, it's possible that the impulse line is off. It's also possible for it to become cracked or split similar to the fuel line. The 025 is an older saw and ten years of service could see this occure. It is located at the base of the cylinder and connects to the back of the handle mount behind the carb. The close end (operator end) pushes up onto a short tube-like nipple. You should be able to inspect it with a flashlight aimed in that direction by placing the saw on it's recoil side. Much easier if the handle assy. is off but should be possible.

If the saw is flooded out, disregard this and forgive my long-windedness

The typical flywheel/ coil ignition system is a "fixed" system. The only adjustment for this is the air gap you mentioned. spec is from .008 to .012 IIRC (I'm certain that the spec. is available online some where, thoughI'll check later today for you from my shop.) The flywheel is a tapered match to the shaft and possesses a key that is machined as a part of it (the flywheel.) I would not try and take it off for any reason as I seriously doubt there is a problem with it. It is possible for the magneto to be bad, but I really have not seen more than one or two since the inception of this series of saw. You have checked the spark and it did. I surmise that it is probably good enough.

Last thought is that when inspecting the piston through the exhaust port, you will know real quick if it's bad or not. The piston should sport the original machine marks when the piston was built, even with lots of use under it's belt.

Keep us updated.

best,
Mark

Take a cut-off wheel and remove that danged 'spark arrester screen' and pitch it in the trash, that's what was wrong with my 044 once, has ran perfect ever since.

Gunner

A saw has to be dependable. If you have tried all the logical things and it doesn't run, take it to someone who fixes them for a living. One thing I can't stand is to travel to a logging site, carry all my stuff into the woods and struggle to get a saw to run. It is a waste of time and money.

I gave up on my old Jonsereds and bought a new Husqvarna. The saw paid for itself in one day.

What folks don't realize is that running the mix too rich (lots of 2 stroke oil) actually has a leaning effect on your air/fuel. You can actually cook a piston with bubba's good intentions (more is better with the oil right?)

Did the old plug have any small aluminum flecks on it?

The collective advice you have gotten here should have you up and running. All I can do is give a +1 to all the comments on the lines (including the impulse line and diaphragm), making sure the crank case isn't wet with fuel, etc.

compression, spark and fuel. If you have those covered you're golden.

Sounds like one of the 3 insufficient in this case.

Some excellent stuff in this thread - thanks guys. My experience with mags is that they either work or don't, so if you have some spark you are probably OK there. A simple hold-in (rubber seal) comp gauge should give you a ballpark reading on compression. If that is decent, and if you are getting fuel squirting into the cyl with each pull, I have to go with the fellows who think that the bottom end is flooded. There are some devils in 2-strokes, and this is one for me. The 2-stroke Polaris ATVs here have a drain plug in the crankcase bottom. When needed, I remove the plug (yes, stuff runs/drips out), crank the engine for a short time with NO FUEL INPUT, and let it sit open for 24 hours. Then, plug in, fuel on, maybe small touch of ether, and it rolls. Hope this helps.

Really? Wow. Poulan has been the biggest POS saws/etc.... we've ever owned and it appears that Sears is a poulan in other clothing often.

I"m amazed at your luck with them.

Sorry I"m OT here but was amazed.

Buffaloed here. You are quite thorough given one is working on borrowed gear. Perhaps if you washed and waxed my pickup your saw would start.

Do let us know if things get rectified.

Good luck,

Saw starting 101 , the quick method.

I never seen a saw that wouldn't give fits every now and again. Mostly operator error.

Problim #1 ?
Miss the chance to turn the choke off starting and flood the saw. Close second, bad fuel in a saw that sat around.

Any saw that don't start. (assuming the fuel is topped with proper freash fuel)

Pick the saw up by the recoil rope.
If the saw comes off the bench and slowly 'putts' back down to the bench, there should be enough compression to run, continue.

Pull the spark-plug.
If you have been trying to start the saw for awhile, it is either going to be as dry as a popcorn fart, or it will be wet fouled ?
Wet-fouled, continue.

Cook the business end of the plug with a propane torch, camp-stove, gass stove or even a few minnutes with a lighter.

Red hot, or near red hot will dry and clean the plug.

Twist that hot plug back in as fast as you can, put the plug-wire back on and start the saw. More offten then not, something happens!

No compression, (scorered piston witb the muff off, no compression on a guage) non-pro Stihl (orange handle) i would prolly scrap the saw.

Dry plug, sometomes sitting around the carb/fuel-pump dries out and won't charge the crank/cylinder. Sometimes dumping a spoon full of fuel down the carb will get a few putts.
Sometimes that breif start/run force the built in fuel pump/carb to wake up.

This right here has been the answer on many saws people have brought me. If they make the fuel mix rich (novice erring on the side of caution when mixing fuel/oil), then you plug the spark arrester screen.

Whenever I lend out a 2-stroke. I always lend out a can of fuel I mixed using premium gas and a quality 2-stroke oil, mixed to the correct ratio.

Update:

Got swamped early at work and didn't get to spend too much time on it. I watched a lot of youtube videos last night/this morning and felt good about doing more indepth stuff on it.

1. removed muffler/exhaust and inspected piston and cylinder with good flashlight. No marks or scores on either so that is good.

2. Removed carb and tore it down. Found trash in the carb along with the diaphram being distorted with a small wrinkle in it. I have a new rebuild kit on order, should be here by the weekend.

3. Pulled cover to inspect/test ignition coil. Everything inside here was filthy, also ignition coil was well outside of specs for gap distance between magnet. Removed coil and cleaned everything out. Re-installed coil and set at proper gap.

I have everything put back together and I am waiting on the carb kit, also got a new air filter, new fuel pickup tube and screen.

Once kit comes in I will rebuild the carb, install the other parts and give her a go. I think this will finally solve the problems. In between now and then I will take the plug out spay cylinder down with carb and choke cleaner and let it air out/dry for a day or so with a rag over the hole.

Thanks so much for all the help on this, I now feel like a stihl rep and would feel good doing a complete tear down of the engine if needed.

I know it seems like I'm crazy for doing all this on a saw that isn't mine and that I didn't mess up, but it belongs to a good friend that always lets me use stuff when I need to.

Working now on buying my own power tools beyond the starter wall mart /home depot type stuff. Got a Stihl 250c coming my way and will pick up a good stihl blower and edger over the summer. Trying to get to the buy once/cry once stage. I don't do a ton of tree cutting or other yard work, but ready to have quality stuff that I can rely on. And "Mikey" ain't comming near any of my stuff.

Matt

From reading the saga... lack of fire is what I continue to suspect but may be incorrect.

I am running a big Stihl for falling and a small Husky for limbing. While I have never had an issue with the Stihl, the Husky was good all day and would not start one week later. Problem was a crack at the fuel pickup in the tank. Replacing all the tubing solved the problem. When removing the fuel lines, all of them were disintegrating. Why the lines in the Stihl are ok is unknown (same age) but will be replaced before using again.

Got to love ethanol.

Maybe "Mikey" put bar oil in the gas tank and then ran it?

Cleaning and regapping the coil is a good idea, but I have never had one where I could see spark and had an ignition problem.

Jerry

Ever get it running? If so, what was the problem?

If it wouldn't even pop on starting fluid with a new plug, my guess is a sheared key between crank and flywheel.

Ok worked on it some more today and still not running. Replaced the fuel pickup and screen, the air filter and rebuilt the carb with with a kit from the stihl shop. I am getting plenty of spark, and finally I am getting air/fuel when I should. I think I have a compression problem. I noticed fuel starting to come out the muffler. I pulled the muffler and notice when the piston moves up into the top of the cylinder it is not sealing and fuel is coming down the side of the piston and out the exhaust.

It looks like "mikey" really screwed this thing up. I think I need to rent a compression tester to tell for sure. Any guess on how much it cost for a cylinder rebuild kit?

Day or two after this thread was posted my step-brother came over, never see him unless he wants something.

Guess what? "Can I borrow your chainsaw"... [bleep].... He doesn't take care his own stuff, much less anyone elses and I HATE loaning things out in general. But what are you supposed to do?

9 outta 10 times they never come back the same and often much worse for wear.



Last time I loaned my snow-blower (neighbor) he sucked the chain into the auger and it took three trips to the repair shop before it was right again.

Last time I leant out my horse trailer, week later I go to use it and one of the chains is broke and it's got a flat.


Swear, better off not answering the door or phone most of the time.

I lent a chain saw to a friend once.

Once.

Old Saying here in the Mtns
"Never loan your chainsaw or your wife, both will come back with a rod throwed in them"

Coach

Anyone wanna comment on the fuel out the exhaust/piston not sealing thing.

I'm thinking running a bad fuel/oil mixture cause some sort problem that messed up the rings on the piston. I'm almost in above my pay grade at this point. Pretty sure fuel ain't supposed to be coming out like that though.