First canceled trip, #2 Cyl spark plug failure

[J0nathan225]

Well I was planning to see a long time friend in Nashville today, got to the plane at 6am prepped, refueled, and topped off oil (7.2quarts). During the runup though when I went to left mag the RPM dropped 220-300 and EGT on #2 dropped 500+degrees. I thought fouled plugs ar first, especially because I didn't look at the egt for some time. I tried clearing the plugs 2-3 times, right side got real clean, by the third check rpm only dropped 25. Left side differnt story rpm drop lessened to the ~220, but still #2EGT dropped rapidly running on the left mag. 

 

Just double checking my thought process:  my #2 cyl's bottom spark plug is not firing correct?  Video posted. 

[RobertGary1]

Just carry an extra plug in the back. You can just swap it yourself. 

-Robert

[jaylw314]

Not the only possibility, but seems likely. 

Word of caution, I always got confused on the starter switch as to which mag was being grounded.  "R" means right mag is running, even though it's in the left of "L".  I realize that means it's the left mag that grounded, but it's always confused me.

IIRC, the left mag fires the lower left plugs (2 & 4) and upper right plugs (1 & 3).

So assuming you know which mag is running, yes it sounds like the #2 cylinder lower plug is not firing.  I carry around a torque wrench with a spark plug socket, a couple crescent wrenches, thread antiseize, and an extra Tempest spark plug (they come nicely packaged with a new copper washer in a durable plastic tube)

Incidentally, with the G2, is there a setting to increase the sensitivity of the bar graph?  That makes the mag check simpler--you'll see the EGT's rise by 30-50 degF when you switch to one mag.  No need watching the RPM's, just makes sure they all go up at the same time.

[gsxrpilot]

1 hour ago, jaylw314 said:

Incidentally, with the G2, is there a setting to increase the sensitivity of the bar graph?  That makes the mag check simpler--you'll see the EGT's rise by 30-50 degF when you switch to one mag.  No need watching the RPM's, just makes sure they all go up at the same time.

I think GEM calls it EGT smoothing.

[J0nathan225]

Well cleaned and swapped 2/4s plugs. All is well after a media blasting and removal of what looked like a large lead ball. I was flying 1.5hrs in the pattern last night mostly rich, I imagine that's what did it. Live and learn!

[Yetti]

What plugs are you running?   On landing roll I will pull the mixture to about 1/4 open.   Also from basic training will do most idle at 1100-1200 RPM   Only go below that for taxi.

 

[J0nathan225]

urem38e 

9 hours ago, Yetti said:

What plugs are you running?   On landing roll I will pull the mixture to about 1/4 open.   Also from basic training will do most idle at 1100-1200 RPM   Only go below that for taxi.