Stihl 075 weak spark

[Kidneycutter]

Hi, in addition to my oil leak I have a spark problem. I’m getting a weak spark then nothing wh3n I ground the plug. I’m guessing the coil maybe faulty - I did put a module in to bypass the trigger unit sometime ago but it’s been running well up to now.
any suggestions on how to solve..?

 

[Kidneycutter]

Hi, I’ve tested the coil and the primary winding measures 4.0 at ohmx2k and the secondary winding is 8.7 at ohmx200k
the manual states the primary winding resistance should be 1.0. Not sure if I’ve done this correctly.
any advice is greatly appreciate,
thanks
just tested again and the primary winding is 1.5

 

[EastCoastSawGuy]

You get nothing when you ground the plug? You should only get spark when the plug is grounded on the cylinder, and there should be no spark when it is not grounded. Is there a lot of hours on the saw? If so, try to move the coil in just a teensy bit, sometimes it make the difference needed.

 

[Kidneycutter]

Sorry, didn’t explain properly. I had a really weak spark when grounded then nothing. Before this I had a build up of chain oil in the cylinder through the pump and it back fired nearly taking my fingers with it. I wondering wether I ve blown the module. Anyway I’ve ordered both coil and module so hopefully one of these will resolve it.

 

[Kidneycutter]

Job done. New ignition chip/module has resolved issue..fat blue spark now!
I think the backfire may have blown the old one.