Could be your coil, but it could be lots of other things too. I would pressure/vac test first. If that holds then I would try to swap in a different known good carb. If that doesn't fix your problem THEN I would swap in a known good coil. Find a running saw that you can swap parts from and then buy a new part after you figure it out.
IF you have a 201tc-m I would check the carb solenoid first. Make sure the o-ring is not damaged. Even then, I had a new one leak out of the box with a fresh o-ring. A thin layer of ThreeBond 1184 at the top of the solenoid where it leaves the carb body sealed it and it now runs perfectly. Be super careful if you try the 1184. A tiny bit getting into the solenoid or the bottom of the solenoid housing could wreck your whole carb.
I am interested in this fix . additionally im haveing an issue where i keep going thru spark plugs.some times i get2-3 days some time a month and a half .any suggestions.Yes thanks to a fix that Giles had tried and worked for me also. If you would like to know send Giles or me a PM. Thanks
Thats nothing try the same exact scenario with the bad parts new 3 times mind you on the lower boom hydraulic cylinder on my aerial lift of Connecticut Bucket Truck.An FYI for anyone else having this problem with Stihl ignition modules.
Not so much as a Question, but a heads up for anyone who is having problems with their Stihl MS201T
I run a Small engine shop and am a third generation small engine mechanic and have never run into one like this. Customer brought me his Stihl saw said it just quit and would not restart. Checked spark (None) Disconnected the module kill wire still no spark. Okay needs a new ignition module. Ordered one postal service ran over that one with fork truck. On to number 2. Installed proceeded to test spark (Nothing) Okay check mounting - good air gap - good continuity from coil mount to cylinder - good No spark. Decided must have a defective module. Number 3 Same results (No Spark) Spent sleepless nights asking myself what I was missing here. Checked all forums for possible other instances of these being bad. Finally I spoke to another long time Stihl Dealer. He knew of and had this happen to him. Stihl has and know they have an issue with the 1145 400 1303 ignition modules for these saws. So before you think you have done something wrong it may not be so. On to Coil number 4 has to be a good one out there. Right? and as pointed out from another forum the flywheel magnets are good.
I have had a number of issues with the Stihl MS201T. I, too, have been working on small engines since I was a kid, and have a small engine repair service, and I currently have a MS201T that is giving me nothing but fits! And, the latest problem is that the ignition module has failed. This saw has been a 4 month project that has cost me a fortune in parts. I have never had a saw beat me, but this one may be the first, for spending another $120+ for an ignition module seems like throwing more good money after bad. I am really beginning to think that Stihl has designed a Boat Anchor here.Thank you so much for the reply..... Yes I've even thought of that... I have a pile of junk 192 s... And I'm right along with you... Will not take a 201 in for repair.... These four saws we're taking in on trade... I personally don't feel that they are worth 120 dollar module... To try to get 250 out of them running..... I have run Stihl saws for over 40 years... I personally feel that after 2011 they all went to crap.... I thank you for your time... And thanks for the info