Hi every one, I've just joined this forum and I hope somebody can help. I have a Stihl MS180A which I bought new on line 2 years ago. I use the saw for fire wood for the house. The saw worked well and was utterly reliable, until it wasn't. I did the usual fault finding and discovered no spark. After replacing the plug still no spark, rather than test the ignition coil I bought a new one. Fitted and gaped, still no spark. I've tested both primary and secondary coil and they're ok. Can anyone suggest anything ?
Kill switch master control left in the off position?
Damaged wire from coil to master control earthing out.
Spring piece that completes the switch circuit of the kill switch come out of place and contacting the brass end of the kill wire when the master control is in run positions.
Had you had any of the saw apart recently before the no run scenario happened?
Damaged wire from coil to master control earthing out.
Spring piece that completes the switch circuit of the kill switch come out of place and contacting the brass end of the kill wire when the master control is in run positions.
Had you had any of the saw apart recently before the no run scenario happened?
Thanks Bob, but no to all of those. I've discovered that the primary coil only has continuity from the iron core to the terminal. In other words when I put the red lead of the meter on the terminal and the black lead to ground no reading , switch the leads around and I get a reading, baffling. Maybe Stihl have inserted a diode in the primary coil circuit for some unfathomable reason
If your replacement coil was an Amazon cheapy, I would not be trusting it.
Pretty simple system, I never put a meter anywhere near a coil if I were to be honest- so either the coil is permanently grounded, the plug is faulty, or there is something messed up with the flywheel, or the HT lead and the spring fitting that connects HT wire to spark plug is not connected.
When the coil swap happened- did the insulator block go on between the coil and cylinder?
Pretty simple system, I never put a meter anywhere near a coil if I were to be honest- so either the coil is permanently grounded, the plug is faulty, or there is something messed up with the flywheel, or the HT lead and the spring fitting that connects HT wire to spark plug is not connected.
When the coil swap happened- did the insulator block go on between the coil and cylinder?