This has got me pulling my hair out !!
The story so far we have a spare ms181 as a last resort back up and a bit of snedding if Req saw ,the bloody thing is about 3 years old no more than 2hrs use if that, still on the original bar and chain that’s how much its done!!!!
Same fuel as the other saws never old stuff , well its always been a a bit unpredictable on the starting front probably why its got so low hours on it anyway a couple of weeks ago I was cutting a few small logs down to size for splitting the saw had been running for Aprox 5 mins I stopped it and as per norm it wouldn’t start right I thought lets see what’s causing this normal tests Ahh no spark good new plug nothing ummm slapped the spark tester on nothing Ahhh the old coil problem disconnected the stop leads on the coil Nothing umm new coil then. Ordered a new Stihl £38 one, fitted and yaaa away we go 1 hour later the thing wont start normal tests and NO SPARK umm must be a dodgy coil I contacted the supplier and a new one sent out ( Top marks to LS Engineering by the way very nice people !! ) new one fitted ran for about a min then NO SPARK Arrrgggghh
if I adjust it /move the coil it will work momentarily SOMETIMES , just to add I am rotating the fly wheel anti clockwise with a drill plug out , if I stop and then try again invariably there will be no spark
Stop wires disconnected
Resistance checks 1.7meg ohms through the coil to earth
1 ohm resistance through earth bolts to coil
2 Ohm resistance through earth bolts to cylinder head
Well I’m sure it can’t be another dodgy coil,
fly wheel (which is where I thought we were going with this) strongly magnetic and coil gap is set to the correct setting feeler gauge set 10 tho Tried various settings no difference !!
So to summarise good earth, all connections abraded degreased and tight stop wires disconnected during test process
New coil, strong magnetic attraction on the fly wheel correct air gap
What else is there !!!!!!!