Stihl 025 not starting

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fishingpol

Minister of Fire
Jul 13, 2010
2,049
Merrimack Valley, MA
So I have an 025 that I use mostly for cutting larger splits down, and occassional scrounge or cutting large piece down for woodworking projects. I used it last probably in December for a little bit. A few things that I will say are bad on my part. I don't use it enough, I leave old gas in it on occassion and I should have used fresher fuel. The last time I used it, it started ok. If I shut it down for a few minutes, it would not re-start warm/hot. It flooded and I had to pull the plug and air it out for a while, but it would restart cold. So it was getting balky last time I used it. Now, if it sits for a while, I can get some brief starting, but not running. I do have a spark.

Today, I picked up fresh gas(89 octane), used the Stihl oil for the mix and I drained all the old gas. I did the normal cold start and got a quick catch on closed choke but it would not run. A few more pulls and nothing. I flipped up to open the choke up one notch, still nothing. I pulled the plug and it was soaked. I dried it out and let it sit for a while. I put it all together and same thing, slight catch on choke and nothing. I have oil/gas coming out of the muffler now. Any recommendations on what to do? Should I clean the muffler?


One of my questions would be if the plug is saturated and it dries off, is there still oil residual that affects the plugs performance? Also does the oil saturate the muffler and cause starting issues until it burns out.

Go easy on me all you heavy hitters. I have no problem tearing stuff apart if needed. I will say shame on me for neglecting the old girl. I can go weeks, if not a month or two between uses. Maybe I'll take out the plug and let it all air out tonight. I put the same gas in my ice auger for a test, and it fires like a champ. Something is not right on the saw. If I can get her to run, I'm sure it'll burn out any junk gas and oil in it. I hope. Thanks all.
 
Have you checking the air filter to see if it's clogged - give it a good cleaning and replace if too far gone. Have you checked your exhaust port and spark screen for buildup? If you screen is clogged or port choked, clean and see what happens. I'd also put a new carb kit in the carb - sounds like a lot of bad gas has sat in the carb for pretty long periods (and for the cheap money, might be worth popping in a new fuel line and filter). At the same time throw in a brand new plug. The above issues can fix a huge number of issues that cause a saw to run poorly and all are super easy. Cheers!
 
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I tried to start it without the air filter, no go. I will pull the muffler tomorrow and give it a good cleaning. The plug is pretty new, but I will change it as it has been getting flooded. Pretty much everything is original, so filters and a good cleaning may be in order. Thanks, I'll see what I can do with it.
 
Don't bother trying to get it started any more. It definitly sounds like problems with the carb to me, especially on a saw that old. I would buy the proper rebuild kit, $12-16, and rebuild it. I've just rebuilt several 024, 025, 026, FS65, 031 carbs myself in the past few months and I had never done one before October. Not that hard for the average newbie. If you want to PM me we can even arrange a time on the phone that I can talk you through it. Its probably a Walbro WT-22X or something like that. You want to get the old one out before you order a kit though. Don't just go by the saw model #-025, they put several different carbs into those things.

You want to take the old one apart to visually check the specifics of the diaphragms, and then check the kit to make sure it has the right one. My local dealers did not have most of the kits for those earlier saws in stock, so I just ordered them a little cheaper off ebay. Got them as fast, or faster, than the dealer could. In most cases, the "white" pump diaphragm with the needed configuration in those saws comes as a "blue" material one. You'll see what I mean if you look at some kits on ebay.
 
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Fishinpol,
I've had a few 025/250s. And they start different then most Stihls. For kicks net time is cold, put the choke on and just pull hard two times. Stop take it off choke and put it in the fast idle mode. Don't listen for burp. Two pulls on choke, next two w/o choke. It will start. Counter to everything I know about saws but it works for that breed for some reason. If that don't help you definitely have a fuel delivery issue. What is the compression?
 
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Don't bother trying to get it started any more. It definitly sounds like problems with the carb to me, especially on a saw that old. I would buy the proper rebuild kit, $12-16, and rebuild it. I've just rebuilt several 024, 025, 026, FS65, 031 carbs myself in the past few months and I had never done one before October. Not that hard for the average newbie. If you want to PM me we can even arrange a time on the phone that I can talk you through it. Its probably a Walbro WT-22X or something like that. You want to get the old one out before you order a kit though. Don't just go by the saw model #-025, they put several different carbs into those things.

You want to take the old one apart to visually check the specifics of the diaphragms, and then check the kit to make sure it has the right one. My local dealers did not have most of the kits for those earlier saws in stock, so I just ordered them a little cheaper off ebay. Got them as fast, or faster, than the dealer could. In most cases, the "white" pump diaphragm with the needed configuration in those saws comes as a "blue" material one. You'll see what I mean if you look at some kits on ebay.

Thanks for the offer Boog. I was looking through Youtube for tear down videos and there were a few there, so I should be good to go there. I looked online and there were a few mentions of 2 diferent carbs on this model. Then I popped over to Ebay and saw the rebuild kits, some OEM and some from China. One guy has a carb rebuild kit, fuel and air filter for short money. I think I have the boat pointed in the right direction. Time to make room on the bench.
 
Fishinpol,
I've had a few 025/250s. And they start different then most Stihls. For kicks net time is cold, put the choke on and just pull hard two times. Stop take it off choke and put it in the fast idle mode. Don't listen for burp. Two pulls on choke, next two w/o choke. It will start. Counter to everything I know about saws but it works for that breed for some reason. If that don't help you definitely have a fuel delivery issue. What is the compression?

I'll try it again before tear down. This saw has always started after two pulls on choke, burp, then one or two pulls on fast idle. As far as the compression, I think it is good. After a few pulls, I can feel it where it needs a good yank to get past it. This is not my area of expertise though.
 
I'll try it again before tear down. This saw has always started after two pulls on choke, burp, then one or two pulls on fast idle. As far as the compression, I think it is good. After a few pulls, I can feel it where it needs a good yank to get past it. This is not my area of expertise though.
If you can post a pic of the cyl after you pull the muffler we can tell you if it's ok. Removing the muff is real easy. After you have the muff off pull the starter cord so you can see the rings and the piston skirt. All easy stuff. Have a go . We can walk you through a complete rebuild ifn ya need.
 
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Nice price. Do you know if the screws are preset on those carbs? Hoping to avoid resetting them. Thanks for that link.

Angelo, I did a two-pull on choke, popped, notched up to high idle, two pulls-nothing. I did this a few times, I'm sure it flooded again. I took off the muffler and took some pics. With the piston all the way up, there was gas bubbling down into the exhaust port. Is this normal? Probably explains the gas dribbling out the muffler. The spark screen is original, I did not clean it. just a little fouling. If my Stihl shop is open tomorrow, I am going to grab a new air filter and plug and take out the plug to air dry the cylinder out. I bet the plug is probably saturated and does not want to work right. My back up plug is probably no better off. I am wondering about the bubbles though. The piston looks clean.


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Thanks for the continued help.
 
If you have fuel drooling out of the exhaust, there would be enough to make it fire.
While at the Stihl dealer, have him do a compression check.
I would bet that it will be a bit too low to run.
 
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Well, good news. I had the plug out, muffler off and let it sit for a few hours. I put it back together, choked, and it popped on the first pull. I went up to high idle and she caught a little. Two more pulls and she fired up, blew smoke for a few seconds and now it runs good again. I did a few hot starts just to try it out and it started each time. I think part of it was pulling more than once on choke maybe flooded it. Fresh gas does make the difference. If it is not going to be used for a while, I will empty the tank back into the container with stabilizer and run til dry.

Thanks for the tips everyone, this is part of what makes this place so great.
 
Sorry I'm late to the party but from the beginning I guess your problem was lack of persistence. ;)

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.
 
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Ha, persistence, that's funny. If anything, I'll be better on the gas situation. It's weird because at the end of the summer I drain the gas from the blower and line trimmer. The snowblower gets drained in the spring. The saw, I neglected it.:(
 
I used to drain my 025 for longer term storage and found the pick-up hose cracks in the tank, and will not pull fuel with the slightest air leak. Now I use the new Stihl oil that is made with the blue stabilizer instead of red. We'll see if the rubber lasts longer. I was replacing it every couple years.
Another thing that stops my 025 is moisture on the mag kill switch wire. Cold saw from cool basement to outside on a warm humid day condensates enough on cold saw to shut it down. Seems a ride on the 4 wheeler from basement to where I'm cutting is just enough to affect it. Blowing it off with compressed air doesn't help. It takes a shot of WD-40 to displace the moisure, and it runs great.
 
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Well, good news. I had the plug out, muffler off and let it sit for a few hours. I put it back together, choked, and it popped on the first pull. I went up to high idle and she caught a little. Two more pulls and she fired up, blew smoke for a few seconds and now it runs good again. I did a few hot starts just to try it out and it started each time. I think part of it was pulling more than once on choke maybe flooded it. Fresh gas does make the difference. If it is not going to be used for a while, I will empty the tank back into the container with stabilizer and run til dry.

Thanks for the tips everyone, this is part of what makes this place so great.
Good on ya. The 025 fooled me a few times too. And I thought I knew saws....if you can do not run ethanol. It's a killer.
Ps that piston looks perfect. Let us know what the compression is and keep a log for when it starts to drop off waaaaaayyy in the future.
 
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