I have done all the electrical checks, stop switch, etc., all okay. Since you seem interested, I'll give you the history. The old 271 is the mid-size saw in my three-Stihl arsenal. When it became hard to start, then impossible to start, I checked compression and it was only 90 pounds, and I figured the saw was finished. Then I located on eBay a brand new 271 crankcase with crankshaft, bearings, seals, rod. piston, cylinder, and carburetor boot from a dealer who cannibalized a saw for parts. Since the price was less than half that of a new saw, I decided to transfer all the external stuff from my old saw to the new crankcase. I could still not get it started. I used the original carburetor and did the simple rebuild with Stihl parts, replacing the metering diaphragm pump diaphragm. The carburetor held 10 psi on a static test. Then I did what I hate to admit was a lot of parts changing back and forth, an after-market carb and an after-market module. I could occasionally get a spark with a neon tester but have yet to see one on a spark plug grounded to the head. At age 84, I got tired pulling on the recoil although the saw is clamped to a steel table. Having a machine shop, I made a splined adapter to turn the flywheel at decent RPM with an impact driver, and a consistent spark was produced. Okay, so the module works at high speed, but not at the speed I would be pulling it in the woods. The Stihl part number you mentioned is on its way now. This brings us to another question regarding spark testing. It would seem the Echo spark tester is the preferred tool of choice by professionals, which I am not, so I also ordered one of those. It's been a great experience, but I would have been better off to trash the old 271 and buy a new saw. Stihl in the US has had price increase on top of price increase.