021 coil problem

[boutselis]

I have an 021 stihl. It sat for a year or so. I drained the fuel and replaced it. It started right up and I set it aside. I went to use it and this time it kicked over with the choke on and then there was no spark.

I replaced the coil. Choked it, it kicked over and then wouldn't start. I checked and again it had no spark.

Is there something that could be causing the coil to burn out? I may have inadvertently switched spark plugs from a larger stihl. Could that be the problem?

Thanks for any help. I really don't want to pay a bench fee to find out what is wrong with a saw that would be worth $200 (tops) in perfect working order.

 

[Rookie1]

A bad or different sparkplug wouldnt make the coil short out. Are all the ground wires hooked up correctly? Also check the on/off switch maybe its shorting somehow. Was the "new" coil new or used?

 

[boutselis]

A bad or different sparkplug wouldnt make the coil short out. Are all the ground wires hooked up correctly? Also check the on/off switch maybe its shorting somehow. Was the "new" coil new or used?

It was a new coil but not a stihl coil. it was an after market.

 

[Rookie1]

If everything in the basic wiring checks out I guess its possible to get a defective part. I wouldnt jump to conclusions without doublechecking everything first.

 

[boutselis]

If everything in the basic wiring checks out I guess its possible to get a defective part. I wouldnt jump to conclusions without doublechecking everything first.

thanks for the reply. It just really seems strange that a coil would die the moment the saw started unless there was something specific causing it.

 

[oscar4883]

x2 on the basic wiring. I would put a new plug in it to maybe eliminate that. How did you set the air gap between the coil and the flywheel? A business card should get you about 0.012 which is close enough. Also, how are you checking the spark? Keep us posted.

 

[boutselis]

x2 on the basic wiring. I would put a new plug in it to maybe eliminate that. How did you set the air gap between the coil and the flywheel? A business card should get you about 0.012 which is close enough. Also, how are you checking the spark? Keep us posted.

thanks for the continuing interest and help.

I used a regular playing card for the gap. not snug. set it so I could slide the card in and out with just the slightest drag. I am going to try a new plug first. thats a good idea. its pretty cheap. I can't see any breaks in the wiring (as someone else suggested I check) so I'm kinda stumped.

It sure would be nice if it was a simple as a bad plug.

do spark plugs burn out like coils do?

 

[Damon]

thanks for the continuing interest and help.

I used a regular playing card for the gap. not snug. set it so I could slide the card in and out with just the slightest drag. I am going to try a new plug first. thats a good idea. its pretty cheap. I can't see any breaks in the wiring (as someone else suggested I check) so I'm kinda stumped.

It sure would be nice if it was a simple as a bad plug.

do spark plugs burn out like coils do?

A dollar bill (3.5 thousandths) will provide you with the perfect gap for a coil playing cards (6-8thousandths) are too thick


Im just gonna throw this out there i dont think you have a problem with spark, i think you have a stihl fuel line itis(cracked fuel line... or the timing is way way off if it kicks over and then dies you have spark

 

[boutselis]

A dollar bill (3.5 thousandths) will provide you with the perfect gap for a coil playing cards (6-8thousandths) are too thick

thanks. I didn't know that.

Could having the gap to wide cause the coil to burn out even after firing just a couple of times?

 

[boutselis]

x2 on the basic wiring. I would put a new plug in it to maybe eliminate that. How did you set the air gap between the coil and the flywheel? A business card should get you about 0.012 which is close enough. Also, how are you checking the spark? Keep us posted.

I forgot to answer one question. I wrapped a copper wire around the threads of the plug and held the other end against the head while I pulled the starter.

the wire was insulated except at the ends. about a 12 gage wire.

 

[Rookie1]

No,too wide of an air gap will just change the intensity of the spark. Even with a wide gap you should have some spark. Plugs do go bad but not often. Thats the easiest thing to change,so try that.

 

[logging22]

Ground wire.

 

[ray benson]

Plug - Bosch WSR6F or NGK BPMR7A gapped to .020"
Air gap between ignition module and flywheel magnets should be .008" - .016"

 

[boutselis]

Plug - Bosch WSR6F or NGK BPMR7A gapped to .020"
Air gap between ignition module and flywheel magnets should be .008" - .016"

thanks. I contacted the place I bought the coil from and told them how it burned out and they are sending me a second coil. Thought that was pretty nice of them seeing my local shop won't do that for me.