I need some help from the resident small engine guys. I am trying to get a friends Stihl 025 to run and need some direction. This saw has always ran like a champ. I have personally worked with its owner while in use and can verify that, and his personal care of tools is top notch.
Scott let 'Mikey' borrow the saw a few weeks back. "Mikey" returned said saw with no mention of any issues. I asked to borrow it this weekend to cut down a small bradford pear tree. Scott gave me a heads up to check the auto oiler as he thought it might be a little caked up with sawdust from "Mikey"s use.
Once I got the saw home and took a good look at it, its was obviously ran hard to border line abused by "Mikey" I removed the chain and bar, got everything cleaned up and put back together.
Saw will not start. I didn't verify that it ran when I picked it up, just put it in the truck as Scott's stuff has always worked top notch. I check the plug and it is fouled VERY heavily. Checked the tank and the 'fuel' mixture is extremely dark and oily. Air filter is also a mess.
New plug from the local Stihl shop, air filter cleaned, tank cleaned out, pickup screen fuel tube to carb cleaned. New non ethanol 92octane with synthetic 2cyl oil to 50:1 spec per the stihl manual added. Saw will still not start. Muffler removed to inspect for obstructions and screen checked out fine as did the gaskets. All re-installed. New plug removed and inspected for spark while engine turns over via pull cord. Spark is noticeable, however I feel it may be weak. Looking for way to test that.
Air filter housing removed to pull carb out and inspect. I notice that the access tube for the low speed screw and the idle speed screw are moved out of alignment to set screws. Makes me wonder if "mikey" tried dicking with the adjustments.
Carb removed, bottom fuel bowl taken off and flushed with carb cleaner, no gunk or gel noticed. Carb re-installed with access tubes correctly aligned to adjustment screws, filter housing re-installed.
I took the top "low speed" screw to factory setting "all the way tight, then backed off one full rotation. I have no real idea of what the idle speed screw should be set at, any help there would be great.
Saw still will not start, I've tried giving it a little ether and it will not run off of that.
From what I can figure, either there is something messed up in the carb or the idle speed setting is way off. Or I have a spark problem. (with plug removed while turned over fuel mixture sprays out the plug hole).
How do I test to see if I am getting enough spark.
Also wondering about the gas tank vent line. I know it has something to do with overall starting and running, but not sure what it should be at. It is a clear tube with two set screws in it, I believe it to be a one way vent tube.
I have very little small engine experience and have kind of reached an end of what I know to do with it. Any help, pointers or folks that want to find "mikey" and kick his butt with me are welcome.
Never, ever lend out a chain saw. Ever. BTDT. Big mistake.
You are doing all the right things. Check for spark in a dark room by grounding the plug base and pulling the cord. Look for a spark. Or if you are manly enough, hold it (not recommended buuuut....)
2-strokes are very simple; if it's got spark and won't at least cough with ether, then the dufus probably scored the cylinder. Check compression...
In a normally lit room, using a screwdriver grounded to the head and the electrode on the screwdriver I can see spark while engine is turned over. It doesn't seem like a ton of spark, considering its a brand new plug.
Besides plugging spark with my finger/hand and bubba checking for compression I have no real way to "test" compression level.
Try to find out if the "mikey" mixed his own fuel and got too much oil in the mix. That'll choke up a carb PDQ. I had a moron do that to me twice with a little 4hp merc outboard.
I don't know the Stihl ratio but the gas/oil mix for my Husky's (50:1 I believe but that's from memory) is just a very light blue.
Also... gas from flooding can kill a new spark plug.
Try a spritz of ether right into the cylinder via the plug hole. Put the plug back it and rip the cord. If it STILL doesn't even cough, it about has to be compression.
Take the muffler back off and inspect the exaust side of the cylinder and the piston for scoring, If you have any he most likley ran it with the wrong oil or no oil in the gas. also check if the plug is wet when after you try to start it w/ the choke on.
Are you sure he didn't lend it to my father? I once watched him mix old motor oil with gas for a 2-stroke. He used my weedeater one time and it came back with the piston skirt in the bottom of the case and what was left of the piston sideways in the cylinder.
I don't know the Stihl ratio but the gas/oil mix for my Husky's (50:1 I believe but that's from memory) is just a very light blue.
Also... gas from flooding can kill a new spark plug.
Try a spritz of ether right into the cylinder via the plug hole. Put the plug back it and rip the cord. If it STILL doesn't even cough, it about has to be compression.
It is 50:1, I downloaded a PDF manual to be sure. I bought premixed fuel from the Home Depot. It is A) 92 octane B) ethanol free C) uses synthetic oil to a 50:1 ratio (you can buy 40:1 as well). I did this as we have not ethanol free gas available, and for small engines I avoid ethanol fuel like the plague!
It would not start with Ether sprayed into the head and the plug quickly installed.
Tomorrow at work I'll pull the muffler/exhaust back off and take a good look at the piston/cylinder for damage.
Take the muffler back off and inspect the exaust side of the cylinder and the piston for scoring, If you have any he most likley ran it with the wrong oil or no oil in the gas. also check if the plug is wet when after you try to start it w/ the choke on.
Yes, when I first pulled the heavily fouled plug it was wet from fuel and every time you would crank it with plug removed it would spray fuel.
I will check it again in the AM to see if it is still spraying. I even removed the fuel screen and just left the pickup tube in the cleaned out tank with fresh fuel.
Not a mechanic but I have used echo products for 30 years... when they are run hard and long with to much oil the exhaust port where the muffler bolts on will clog up with carbon and crap and will not run. You said you checked the muffler and screen did you remove the muffler and check the port for buildup clogging it up? Maybe that will help.
New bosch plug is properly gapped and installed, still will not crank. Plug shows spark when tested outside of combustion chamber, just not sure how to test to see if it is enough spark.
The problem is the fuel line from the tank to the carb. Being this is the spring the saw has been sitting all winter. The problem is the ethonanl in the gas. The gas line rubber gets eaten and soft. I have changed a whole bunch of those on sthild that have had gas left in them. And you can say you drained it all out but you really never do. The gas line has a series of knots molded in the line. check for cracks around those knots.
I removed the pickup tube from the tank to the carb. It was not obstructed, re installed. The saw was used and ran fine prior to "mikey" getting his hands on it.
From imput from others I'm thinking he ran improperly mixed fuel in it and that may have caused some real problems...
I applaud you for being so thorough in your procedure to check out the unit. Many folks are not.
The major problem I see on the 025 series are usually related around fuel issues that are substandard in nature(read aged.) As grizz (and others suggested) the fuel line could have some checking issues. Look around the bended areas out of the tank. Sounds like you might have done this already?
Do take the muffler off again to inspect the cylinder. If it looks ok, take a turn at starting. Turn the saw on (no choke-just on) and hold throttle wide open. Then crank the "sucker" (technical term ) 15 or 20 times, or until it starts to try to start. The saw's cylinder and crankcase might be so flooded that it is wetting you plug too much for it to fire properly. If the spark is good and the compression is reasonable, it should try to start. Keep it up until it starts to clear out. I'm guessing that this is your problem, though I'm assuming that the carb. is clean and the diaphrams are not warped or have issues.
Good advice from bearhunter here. When you pull the exhaust off turn the saw with the exhaust port down. With the plug out and crank it and see if you get premix out of it. If so, continue to crank until it dries up. Those carbs have tiny passages in them too and not hard to clog up. Way back in the 70's, I saw guys turn their bikes upside down and crank them to clear the bottom ends of fuel. The old CZ bike actually had a drain plug in the bottom of the motor for flooding.
I need some help from the resident small engine guys. I am trying to get a friends Stihl 025 to run and need some direction. This saw has always ran like a champ. I have personally worked with its owner while in use and can verify that, and his personal care of tools is top notch.
Scott let 'Mikey' borrow the saw a few weeks back. "Mikey" returned said saw with no mention of any issues. I asked to borrow it this weekend to cut down a small bradford pear tree. Scott gave me a heads up to check the auto oiler as he thought it might be a little caked up with sawdust from "Mikey"s use.
Once I got the saw home and took a good look at it, its was obviously ran hard to border line abused by "Mikey" I removed the chain and bar, got everything cleaned up and put back together.
Saw will not start. I didn't verify that it ran when I picked it up, just put it in the truck as Scott's stuff has always worked top notch. I check the plug and it is fouled VERY heavily. Checked the tank and the 'fuel' mixture is extremely dark and oily. Air filter is also a mess.
New plug from the local Stihl shop, air filter cleaned, tank cleaned out, pickup screen fuel tube to carb cleaned. New non ethanol 92octane with synthetic 2cyl oil to 50:1 spec per the stihl manual added. Saw will still not start. Muffler removed to inspect for obstructions and screen checked out fine as did the gaskets. All re-installed. New plug removed and inspected for spark while engine turns over via pull cord. Spark is noticeable, however I feel it may be weak. Looking for way to test that.
Air filter housing removed to pull carb out and inspect. I notice that the access tube for the low speed screw and the idle speed screw are moved out of alignment to set screws. Makes me wonder if "mikey" tried dicking with the adjustments.
Carb removed, bottom fuel bowl taken off and flushed with carb cleaner, no gunk or gel noticed. Carb re-installed with access tubes correctly aligned to adjustment screws, filter housing re-installed.
I took the top "low speed" screw to factory setting "all the way tight, then backed off one full rotation. I have no real idea of what the idle speed screw should be set at, any help there would be great.
Saw still will not start, I've tried giving it a little ether and it will not run off of that.
From what I can figure, either there is something messed up in the carb or the idle speed setting is way off. Or I have a spark problem. (with plug removed while turned over fuel mixture sprays out the plug hole).
How do I test to see if I am getting enough spark.
Also wondering about the gas tank vent line. I know it has something to do with overall starting and running, but not sure what it should be at. It is a clear tube with two set screws in it, I believe it to be a one way vent tube.
I have very little small engine experience and have kind of reached an end of what I know to do with it. Any help, pointers or folks that want to find "mikey" and kick his butt with me are welcome.
Do you want to borrow some all of my broke schitt?
I applaud you for being so thorough in your procedure to check out the unit. Many folks are not.
The major problem I see on the 025 series are usually related around fuel issues that are substandard in nature(read aged.) As grizz (and others suggested) the fuel line could have some checking issues. Look around the bended areas out of the tank. Sounds like you might have done this already?
Do take the muffler off again to inspect the cylinder. If it looks ok, take a turn at starting. Turn the saw on (no choke-just on) and hold throttle wide open. Then crank the "sucker" (technical term ) 15 or 20 times, or until it starts to try to start. The saw's cylinder and crankcase might be so flooded that it is wetting you plug too much for it to fire properly. If the spark is good and the compression is reasonable, it should try to start. Keep it up until it starts to clear out. I'm guessing that this is your problem, though I'm assuming that the carb. is clean and the diaphrams are not warped or have issues.
Try to find out if the "mikey" mixed his own fuel and got too much oil in the mix. That'll choke up a carb PDQ. I had a moron do that to me twice with a little 4hp merc outboard.
This is my guess. The easiest way to screw up any borrowed two stroke has got to be improper fuel mixture. If you're lucky, you can drian the gas and fill it up with the correct mixture. Hopefully, with a few pulls, you can get her started up again.
The part about not firing with ether means either the spark is too weak to fire under compression, or it's loaded up so bad it drowns the spark with fuel.
Guys thanks so much for the input, giving me good places to start with it this morning.
I watched the video on how to rebuild the carb. Looked surprisingly easy. I've never had to mess much with carborated equipment, will tear down this carb to inspect for damage a rebuild kit should be simple to buy and install if needed.
Will be checking the cylinder to look for damage, googling images right now to see what a screwed up one looks like. Hoping that isn't the issue, but have a bad feeling it might be.
I will look at our shop to see if we have a compression tester I can fit to that stihl, but I doubt it. Looking online I should have around 125-150PSI
Also will try turning it over with muffler removed and plug removed to see if that helps break anything up and move it out.
Only reason I am doing all this is the saw's owner Scott, is a very good friend and I KNOW this saw has been well taken care of in the pass. I had a feeling our mutal friend "mikey" was someone I wouldn't loan stuff to and this ordeal has more than confirmed that!
I just bought a NOS Stihl 250c so no more borrowing chainsaws for me, and it dang sure won't be lent out to bone heads like 'mikey'.
Oh and for anybody following this thread, Lil' Red Barn has some great videos on You Tube and parts for just about any outdoor power equipment it seems.
Good advice from bearhunter here. When you pull the exhaust off turn the saw with the exhaust port down. With the plug out and crank it and see if you get premix out of it. If so, continue to crank until it dries up. Those carbs have tiny passages in them too and not hard to clog up. Way back in the 70's, I saw guys turn their bikes upside down and crank them to clear the bottom ends of fuel. The old CZ bike actually had a drain plug in the bottom of the motor for flooding.
^^^ Small two strokes can be extremely finicky when they're flooded out. I even throw some raw gas in the cylinder while cranking it to help dry things out.
After doing this try starting it with no choke or throttle until it sputters.
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.
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.
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.
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.
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
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.
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.
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.
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.
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.
Well I had my doubts about him, but this fiasco has let me know for sure he won't be using any of my tools. I hate to have to tell Scott the owner of the saw the bad news. I've kept him up to date on everything, but was really hoping the carb kit and new fuel lines ect. would fix it.
With a flooded saw you can take the plug out and pull the engine over several times. It will blow all the excess fuel out of the plug hole. Then turn the saw upside down and pull it over. Once it stops spewing, dry the plug off as best you can and reinstall it. Set the choke/ignition to the high idle position (all the way down, then 1 up) and pull 'till she fires. Saw will fire within 5-6 yanks 99% of the time.
And with the 025 and like saws, I'd do all the pulling/spewing with the air filter off to avoid it getting soaked with pre-mix.
Now I just have to get the idle adjusted. It will run fine but once you let off the gas it won't stay idling for long.
Never lend a saw or gun out or anything for that matter,and if in doubt on a saw and problems,take it to a saw shop.A person can do more damage trying to save a dime than one thinks coming from a guy that used a chain saw his whole life for a living.My sons best buddy is the Sthil dealer here and talk about basket cases people bring in......Dang.....
Matt from everything you described it sounds like you have a carb issue, been through it 2 times now. Bite the bullet and replace the carb, you'll be saving yourself the headache that will most likely still keep coming if you don't. Replaced a Honda string trimmer carb and a cub cadet (Kawasaki) carb, both run great now. A good small engine mechanic should tell you to not waste your time cleaning and repairing these small carbs, it's the ethanol causing most of these problems. The one carb was "fixed" and the other I told them to replace after the Honda carb still kept giving me fits, so both are now replaced and run and service like new. Most new carbs are about 60-90 bucks.
Got it running now. If you read back I did rebuild the carb.
From everything I've gathered problem was caused by a not only bad ration fuel mixture but also debris in the fuel. Replaced spark plug, fuel lines filters rebuilt carb and replaced air filter. Also reset the ignition coil to within spec.
Got the idle adjusted and the saw is running like a champ, like it always did before 'mikey' borrowed it.
Scott the owner of the saw is a very good friend that has been there for me in more ways than I can count. To be able to fix this problem for him did way more good for me than it did for him.
) 15 or 20 times, or until it starts to try to start. The saw's cylinder and crankcase might be so flooded that it is wetting you plug too much for it to fire properly. If the spark is good and the compression is reasonable, it should try to start. Keep it up until it starts to clear out. I'm guessing that this is your problem, though I'm assuming that the carb. is clean and the diaphrams are not warped or have issues.