026 Cuts out/Dies on "Run", runs on other settings.

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MAD MARK

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I was cutting up a large cherry tree, 1 and half tanks of gas through the saw doing so; i went to shut off the saw to reposition some wood and the kill switch would not do it. So, I used the full choke setting to bog it down.

Went to restart and would not stay running in the "Run" setting. Will run in "Full Choke" and "Part Choke" (seems like higher than normal revs though) but as soon as I blip and it comes into the "Run", it quickly dies down.

Ive checked the tank breather, throttle linkage, spark plug, possible grounding of the wires when in "Run" mode and found nothing. I just changed them (fuel and impulse) last year using Stihl lines. Is this an impulse line breach?
 
Throttle linkage, choke linkage or butterfly is buggered up by "choking it to death"?
While you have it apart a bit, check the wiring for the kill switch.
 
So it’s currently running lean in the on position if it runs choked. Some how somewhere it’s getting too much air to fuel mix. To get to full choke to kill it you should have had the trigger at WOT to push the control latch down. Did you do that or, instead, force the latch down? That could likely be your culprit if so. Check the butterfly in the air filter to see if it’s damaged, popped out or the spring broke or again popped out. There is no linkage to the choke on the 026. The butterfly is in the air filter which is controlled by the control latch directly.

Failing this, check the fuel line for cracks or if it’s slipped off the fuel intake barb slightly. Check the tank vent for function too. Then check the manifold between carb and cylinder for cracks or to see if it’s loose and this disconnected at either the carb or cylinder end. Also worth running a pressure and vacuum test.
 
I'd proceed with caution.

If it's not electrical, you may have a bad air leak, or fuel delivery problem, and running the saw could do damage.

Remove Air filter cover, put in run position. Take a multimeter and check continuity (ohms) from short circuit wire on throttle shaft to cylinder (ground). This wire run to coil, and grounds coil to kill spark. In run position it should not be grounded. If there is continuity to ground, there is a problem in the wiring/switch.

If wire is not grounded you have a lean condition, either fuel delivery or air leak. Don't run saw until you identify source/fix it.

P.S. MERRY CHRISTMAS EVERYONE!!!
 
So it’s currently running lean in the on position if it runs choked. Some how somewhere it’s getting too much air to fuel mix. To get to full choke to kill it you should have had the trigger at WOT to push the control latch down. Did you do that or, instead, force the latch down? That could likely be your culprit if so. Check the butterfly in the air filter to see if it’s damaged, popped out or the spring broke or again popped out. There is no linkage to the choke on the 026. The butterfly is in the air filter which is controlled by the control latch directly.

Yes when I killed with with Full Choke I did WOT and then pushed latch down. I thought also that control latch broke or skipped, but after checking it out everything looks fine.

Remove Air filter cover, put in run position. Take a multimeter and check continuity (ohms) from short circuit wire on throttle shaft to cylinder (ground). This wire run to coil, and grounds coil to kill spark. In run position it should not be grounded. If there is continuity to ground, there is a problem in the wiring/switch.

Ill get to this later today. When I had the air filter off checking to make sure nothing "slipped" on the position switch I did check the wires to make sure they weren't pinched or or grounding themselves out. I should have checked for continuity then.

If wire is not grounded you have a lean condition, either fuel delivery or air leak. Don't run saw until you identify source/fix it.

I just dont understand how either of these could happen while I was a tank and a half in.
 
So I pretended I was taking care of stuff in the garage, so I took apart saw a little and am getting continuity between the YELLOW wire and block. So I took wire off and did what my picture is showing and still getting continuity. So does that mean that the coil is bad? Its grounded itself out? I didnt take that off yet as the kids were yelling in the house as the wife it trying to cook something.
 

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You should have continuity there. Good news is your coil has a good ground.

You need to put that wire/screw back on, that is the ground wire to the on/off/ throttle switch, it connects to the spring in the airbox.

The cutout wire goes from the coil (spade connector black wire), to the throttle shaft. When the throttle shaft is in off position, the cutout wire should contact the spring, grounding the coil.

You can put throttle in run position, check continuity on coil spade connector to ground or at the cutout wire on throttle shaft. Should be open circuit on run, grounded on off position.

EDIT: that screw you removed mounts the coil, which can pivot, so you can adjust air gap at coil to flywheel ( ~0.12"). Both screws actually....

Hopefully it has not moved. After you put the screw back in, turn the flywheel until the flywheel magnet lines up with the coil pickup/mounting arms, should ~0.012" gap. Don't fiddle with it if it's close to 0.012". If it has closed up you need to re-gap it.
 
The yellow loop should only have continuity back to the black lead when in "OFF", In any "RUN" position the black wire shouldn't have continuity to either the yellow or case ground.
A good visual on the intake boot between the carb and cylinder is in order. It sounds like a lean condition. If so pulling the muffler to check the piston thru the exhaust port will be next.
 
The yellow loop should only have continuity back to the black lead when in "OFF", In any "RUN" position the black wire shouldn't have continuity to either the yellow or case ground.
A good visual on the intake boot between the carb and cylinder is in order. It sounds like a lean condition. If so pulling the muffler to check the piston thru the exhaust port will be next.

If switch/wires are O.K. then it's air leak or fuel.

Hopefully the piston looks O.K.
 
Did you by chance have had the saw pinched and pulled or jerked it. Either way I'd suggest taking a good look at the intake boot for damage or it could of slipped off below the clamp..

Yea I had a slight pinch. I turned off (Full Choked out) the saw. Got it unstuck, moved some wood around and then wouldnt run right again.

It is not grounded in run position. Wiring and such seems fine.

I didnt notice any play in the coil in relation to the flywheel but will double check for the 12 when back together. Thanks.

After looking around some, it seems that the impulse line was completely NOT connected. I put it back on and will have to wait to try it out as the kids are sleeping. I will report back what I find because there is nothing good about an OP who doesnt tell the solution in the end.
 
Yea I had a slight pinch. I turned off (Full Choked out) the saw. Got it unstuck, moved some wood around and then wouldnt run right again.

It is not grounded in run position. Wiring and such seems fine.

I didnt notice any play in the coil in relation to the flywheel but will double check for the 12 when back together. Thanks.

After looking around some, it seems that the impulse line was completely NOT connected. I put it back on and will have to wait to try it out as the kids are sleeping. I will report back what I find because there is nothing good about an OP who doesnt tell the solution in the end.
Fingers crossed it is this :) it would explain a lean condition because it wouldn’t get enough fuel, and choked means that what did come through would have less air to mix with so it would combust :) that said, the high idle shouldn’t technically work, but it does?! Interesting, can’t wait to hear!
 
Yea I had a slight pinch. I turned off (Full Choked out) the saw. Got it unstuck, moved some wood around and then wouldnt run right again.

It is not grounded in run position. Wiring and such seems fine.

I didnt notice any play in the coil in relation to the flywheel but will double check for the 12 when back together. Thanks.

After looking around some, it seems that the impulse line was completely NOT connected. I put it back on and will have to wait to try it out as the kids are sleeping. I will report back what I find because there is nothing good about an OP who doesnt tell the solution in the end.


Your not the first one to dislodge an impulse line whilst yanking a saw out of a bind, or intake boot moved, and or torn, av rubbers damaged or torn etc etc etc.
if it gets pinched, just get a wedge in there and open it up, or remove power head, then have at it with some brute force and ignorance pulling the bar straight out.
But dont just yank a saw out of a bind, stop, relax, assess the situation and accept that its going to take some time to remove. If not, your going to take some time later repairing your saw, your call :)
 
But dont just yank a saw out of a bind, stop, relax, assess the situation and accept that its going to take some time to remove. If not, your going to take some time later repairing your saw, your call :)
I didnt pull that hard at all; no harder than ever before ;) This is why I figured it to be messed up linkage of sorts. I ended up using a wedge to get it free. Still didnt fire it up, family came over before kids woke. Stay tuned tomorrow haha.
 

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