MS270 stutters at WOT, but not when in wood

[4lane]

I have a MS270 that starts, runs, idles perfectly. When you pull the trigger full throttle it will stutter. Waaaaaa stop, waaaaaaaaaaaaaaaa stop, waaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa stop, waaaaaaaaaaaaaaaaaaaa stop. It's almost like it's hitting a rev limiter or something. But when you put in wood at full throttle it does not stutter. It will run wide open just fine when cutting under load.

It has never done this before. Any thought on what might be the issue here?

 

[cuinrearview]

Either an air leak and you're hitting the rev limiter (not sure if it has one), a dirty air filter causing an overly rich condition, or your coil is going bad.

 

[4lane]

I was thinking it was an electrical issue too, as I just recently put in a new coil after the original went bad. But that doesn't explain why it would run WOT without stuttering when under load.

 

[cuinrearview]

The drop in RPM could be enough. Did you use an OEM or aftermarket coil?

 

[4lane]

The drop in RPM could be enough. Did you use an OEM or aftermarket coil?

It has a Proline coil in it right now.

https://sawzillaparts.com/proline-ignition-coil-for-stihl-ms270-ms280-chainsaw-1133-400-1350/

 

[cuinrearview]

I'd contact Sawzilla

 

[4lane]

I'd contact Sawzilla

Yep, already did that after you pointed to the coil. And they've already put a new one in the mail for me to try. Good guys down there.