Hard run Stihl ms251

[Fmac]

I was brought an ms251c to check why would not run. They brought a new carb and plug. I took one look at this saw and immediately saw a machine that had been run with no maintenance. Had to scrape saw dust and oil debris out of everywhere. No filter in tank ,bar discolored, sprocket worn down to core, pump drive melted, and no spark. When I removed the old carb had to scrape the filter screen clean ,was completely clogged. Did an engine vacuum and pressure test and both failed. Customer said fix whatever it took. I immediately saw was going to be a challenge. After thorough cleaning and many new parts still have one problem I seem to either missing or this saw is haunted i put a new coil in also. Neon tester shows good coil but still no spark. I have tried everything still no spark. Any suggestions?


Fmac

 

[sharpedge]

Okay, it seems like you've got a good handle on things. I would just double-check that the flywheel key is lined up right, the kill switch wires are good, and the coil air gap is set like it should be. Also, a stop wire that's touching the ground or is messed up could stop the spark.

 

[Fmac]

Already checked. This saw is giving me a run for my money. I am waiting for another coil to see if maybe the coil I put on went south. I checked when I first put it on and to my recollection there was a spark then. Will keep up to date with this haunted saw.

 

[MidlifeMoto]

I see that you've done everything, but yeah, if there are still no sparks, the ignition module itself is usually the one that failed and needs to be replaced

 

[Alan]

That saw sounds like it’s seen better days! I’m really interested to find out if that second coil will do the trick and revive it.