I was told that about my 251 and a new AM coil fixed it just fine. Worth ruling everything else out first, but this insistence that OEM Stihl coils rarely fail can delay diagnosis by chasing everything but that. In this case, an AM coil did nothing for it (cheap under $10 test I can return) and I do see good spark in the dark so not really my tester lying in this case. I know the flood prone issues of the 250 but most all my issues with flooding saws I've found that throttle on the trigger usually gets around it. I've cleared things by starting repeatedly with the plug out, let dry, switched plugs, and still nothing. Would be inclined to agree with you about flooding, but if so, man, this is the trickiest saw to unflood I've ever used. No such issues with my 251. Cleared the cylinder with a lot more pulls, will let dry out longer. Plug was definitely drenched as could be last time I pulled it out. Did a sloppier quick job of diagnostics than usual but that's because I just thought this saw was a starter cord repair and worked fine one day after repairing it. Then it didn't, then it did, then it didn't again. Without concentrating on flooding as the most likely culprit, I jumped too quick to coil without a really good spark test of it.