Stihl 025 Chainsaw Help

[XB 2002]

I have got a Stihl 025 Saw. It does not fire if I hold the spark plug or screwdriver in the boot and crank it slowly to shock myself. Coil pickups are clean and the flywheel. Appears that the wires are in good shape(Not grounding anywhere) Is there any other reason it would not fire ? A new coil is almost 90.00 from my local dealer. Any advice appreciated.

Thanks,
XB 2002

[RonAyersMotorsports]

Take to your dealer before your purchase an expensive part you may not need. Coil replacements on this saw are not that common. You may just have a bad fuel line.

[Phil G]

I have got a Stihl 025 Saw. It does not fire if I hold the spark plug or screwdriver in the boot and crank it slowly to shock myself. Coil pickups are clean and the flywheel. Appears that the wires are in good shape(Not grounding anywhere) Is there any other reason it would not fire ? A new coil is almost 90.00 from my local dealer. Any advice appreciated.

Thanks,
XB 2002


Hi, you might be cranking too slow. These coils need 300 to 350 rpm to produce a good spark.

Remove the ground wire from the coil when you test. This will eliminate any grounding faults.

Check gap coil/flywheel. 10thou ish.

Good luck, Phil

[XB 2002]

Thanks for the reply guys. Ron, I understand what you are saying but if it is a coil and I take it to a dealer the bill will be 150.00 give or take. I know the fuel line is good and I have cranked like I am trying to start it with no fire or shock. There must be a test I can do with a OHM meter to tell if the coil is bad ?? The saw is probably 15 years old but probably no more that 30 hrs of use. How would a dealer determine if it was the coil ?

thanks,

XB 2002

[BigFish]

There is no reliable test. Just hook it up to a simple spark checker and yank like hell. No spark..no good. Purdy simple huh? Of course you narrowed it down to ign. problem, no?

[mowerknower]

Buy your self a spark tester, they arent that much. A lot cheaper than a new coil. I cannot count the times a customer brings a machine in saying it has no spark but when I put the spark tester on I get good spark. Those are the same type of people that usually end up spending more money on parts than they would have spent if they would have just brought it into the shop in the first place. Its pretty funny, first they come in and buy a spark plug and air filter, next they come in and buy a coil, then they come in and by a fuel line, next its a carb kit and then a carb. Then they usually find out they have no compression and the machine is pretty much shot, but they feel so guilty about wasting all that money that they end up rebuilding the whole saw. Final price is usually about 2x that of a new one.

[jkilov]

There must be a test I can do with a OHM meter to tell if the coil is bad ??
Yes the resistance of both circuits can be measured. You'll need a service manual where the range is specified, though they're similar for your average size coil. For some reason this test isn't that reliable. Take the coil off, clean all contacts, coil mounting taps included and the on-off switch then try again.

If you own a decent number of hand helds, invest in a spark tester and compression gouge. They're your basic tools and tell a lot. I have them and I'm not a dealer.

Makeshift copy techniques are squirt of fuel in the cylinder to test fuel delivery. 4-stroke oil in the cylinder to check if compression improves. And looking at spark + resistance measurement for ignition. Not very reliable tests any of them.

Don't fix until you located the problem. Take it to the dealer for diagnostics and after $50 you know where you stand. You'll worry about sourcing parts later.

[RonAyersMotorsports]

Listen to Phil disconnect ground wires. Pull if no spark coil is bad. This is a reliable easy way to test coils for fire. It will not test if fire is breaking during running however. But If you got fire, fuel, and compression it will run. Try spraying fuel directly into carb throat first and see if the unit will hit. If it hits you have fire and you have a fuel problem not spark. I'm with "mowerknower" on this. All to often customers spend more money trying to fix the problem themselves than it would have cost for the shop to fix it in the first place.

[wildncrazyguy]

If you are original owner of the saw, I'm pretty sure coil is warranteed for lifetime of the saw. You should take it to Stihl and check to make sure I'm correct and what the cost is or at least inquire. Probably the part is warranteed, not the labor, but not sure. Good luck. Oh, this site can also help. There are a bunch of good guys as is this site. http://www.arboristsite.com/forumdisplay.php?f=9

[RonAyersMotorsports]

Lifetime warranty on coils only applies on units purchased after I believe 2003 for the original owner only.

[XB 2002]

Damm !! Just my luck, I am the original owner but I bought the saw around 1992 or 93 I think. Thanks for all the advice Gentlemen I will check it all out. The good news is I really don't need it much anymore except for after Hurricanes so I have some time to investigate and look around, I wish I knew someone who had the same just to try another coil.

Thanks,
XB 2002

[rjxj]

Like someone else said, remove the kill wire from the coil to test, be sure the air gap is correct, be sure the magnets are magnets. Also remove the coil and clean the back of the coil and the mounting surfaces. After that buy a coil.