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General Forestry => Chainsaws => Topic started by: Rockn H on September 25, 2008, 11:00:20 PM

Title: Stihl dies
Post by: Rockn H on September 25, 2008, 11:00:20 PM
I've got a Stihl 025 that's about six years old.  It has suddenly started going dead after about 15 seconds.  It starts real good, but when it goes dead it's dead.   You have to leave it alone for a few minutes and then it cranks right back for another 15 seconds.  I need a little brain storming.

Thanks
Title: Re: Stihl dies
Post by: sawguy21 on September 25, 2008, 11:39:00 PM
First pull the muffler and check for piston or cylinder damage. If o.k. you likely have a fuel supply problem. Is the fuel line cracked? Is the fuel filter in the tank plugged (remove it and try running the saw)? Is your fuel mix fresh (within 30 days old)? The 025 is an older model, has it been serviced regularly?
Title: Re: Stihl dies
Post by: sawmilllawyer on September 26, 2008, 12:01:20 AM
If it still does not run properly after doing what Sawguy21 says then check coil. Basically gets warm shorts out and the saw dies. Hopes  this helps. Andy
Title: Re: Stihl dies
Post by: joe_indi on September 26, 2008, 01:56:45 AM
If I guess it right, this is what happens:
You put it on choke, pull the starter, it fires.You move the switch away from choke.You start her up again, the engine dies after 15 or so seconds.
This happens always.

If this is what really happens the impulse hose has come off the connector on the handle housing(the cover on which the carb is fitted).The hose probably came off due to some extra jerk on the handle.
This hose is visible if you look between the top of the fuel tank and the bottom of the handle housing.
You will need to loosen the buffer screws and two screws below the handle base to fit the impulse hose back onto its connector.

Joe.
Title: Re: Stihl dies
Post by: Rockn H on September 29, 2008, 09:11:36 PM
Sawguy21, the saw is 5 yrs old.  I checked the fuel line first and thought it was cracked so I replaced it along with the filter. That didn't change a thing.  Next was to pull the muffler and checked it along with what I could see of the cylinder and piston.

sawmillawyer, I haven't thought about the coil.  I've had a boat motor go bad before.  It would be easy enough to check.

joe_indi, You guessed right except once you crank it, you don't have to choke it anymore, just wait ten minutes. ;D  The guy at my local saw shop mentioned this hose, but I can't find one.  I caught him pretty busy the other day and he didn't have time to look up a schematic.  Then he wasn't sure if my saw had one. ???  The only hoses I can see on top of the tank are the vent hose, the return line from the primer and the main fuel line.  The first two are next to the filler cap side.  The only thing I see one the handle housing are the kill switch wires.  Where would this hose be in relation to the kill switch wires? 

Thanks guys.
Title: Re: Stihl dies
Post by: isawlogs on September 29, 2008, 09:17:44 PM

 I have an 025 here and will look at it in the morning and see if I can find the hose that Joe is talking about .  :P
Title: Re: Stihl dies
Post by: Rockn H on September 29, 2008, 10:17:41 PM
isawlogs, I appreciate that.  I've got to leave out about 4am myself, but as soon as I get back I'm going to have to take another look for it myself. ;)  If all else fails I may even take it to a professional. ;D
Title: Re: Stihl dies
Post by: joe_indi on September 30, 2008, 10:18:35 AM
Rockn H ,
I can vouch for the 025 having an impulse hose.It might not be visible when you remove the carb, since it is connected to the body and the passage reaches the carb on the edge of the inlet manifold as a small hole.
If you can get the carb off the saw, try this simple test.
You should see a small hole on the edge of the manifold (between the 2 studs that hold the carb), once you have the carb out.
Use an oil can to pump oil into this hole. If the oil starts coming out between the engine civer and the fuel tank, either the impulse hose is come off its connector or it has a leak.
Have a look at both these images. You should be able to get an idea of how the impulse hose is connected.

Fig 01:
(http://www.forestryforum.com/gallery/albums/userpics/15459/Impulse_hose_01.JPG)

Fig 02:
(http://www.forestryforum.com/gallery/albums/userpics/15459/Impulse_hose_02.JPG)

Joe
Title: Re: Stihl dies
Post by: isawlogs on September 30, 2008, 10:24:54 AM

  I went and looked at mine before Joe posted , I was going to take the carb off , but sure wont now , thanks Joe , that is about as clear as one can make it .  :P   8)
Title: Re: Stihl dies
Post by: Rockn H on October 03, 2008, 05:17:34 PM
Joe, those pics were just what I needed.  Thanks alot.  I don't know why I kept thinking the impulse hose came off of the fuel tank itself.  I found the hose and it seems to be connected.  I was really hoping it wasn't.  I also checked for spark while it wasn't wanting to crank, and I found some.  So I took it to the shop. :(  They do good work, but it sure is the wrong time of the year around here.  They are so backed up.

Thanks again.
Title: Re: Stihl dies
Post by: joe_indi on October 03, 2008, 11:59:37 PM
Rockn H ,
Here a couple of other things to check out.
Incidentally, is the spark plug wet or dry? If its wet it could be a electrical problem such as :
A bad plug, a shorted stop switch wire, or, at the worst, a ignition module ready to die.
or
A fuel related problem such as:
A slight over flow caused by a poorly seating metering needle.
or
A compression related problem due to a small seizure of the piston.

If the plug is dry it is usually a fuel related problem such as:
A blockage anywhere, from the tank upwards.
Or a air leak, usually in the oil seals, or, as in the case of short block engines such as the 025,a leak between the cylinder and the engine pan.These are held together by 4 screws at the bottom of the saw.
Two of them are accessible but for the other two you will need to remove the handle .
For a 6 year old 025, I would suspect this because these screws do tend to become loose.
Sorry for being long winded .
I was thinking off the top of my head while I typed.
Joe