Paul Eastham
Well Known Member
You know, the ferrule, the little metal bit at the top of the plug where you plug the wire in.
I just checked my plane -- four out of four were loose and wobbly.
They are brand new NGK plugs replaced at annual only ~5 hours ago. I didn't notice them to be loose when I installed them, but didn't explicitly check them for this. And I've been using this brand/type for the past 10 years, never noticed this before.
I recently had some ignition trouble (old thread here) which I think was caused by this. First I thought it was caused by ignition wires (two of them were indeed flaky when bent just right so maybe I prevented a future failure there), then I thought it was the Lightspeed coil (one coil was indeed bad), but the root cause, according to Lightspeed, was probably the loose ferrule which causes heating in the coil and failure.
And of course who knows what kind of weak spark you get when that thing is loose...hopefully a gentle turn with a pair of pliers will keep them in place.
I just checked my plane -- four out of four were loose and wobbly.
They are brand new NGK plugs replaced at annual only ~5 hours ago. I didn't notice them to be loose when I installed them, but didn't explicitly check them for this. And I've been using this brand/type for the past 10 years, never noticed this before.
I recently had some ignition trouble (old thread here) which I think was caused by this. First I thought it was caused by ignition wires (two of them were indeed flaky when bent just right so maybe I prevented a future failure there), then I thought it was the Lightspeed coil (one coil was indeed bad), but the root cause, according to Lightspeed, was probably the loose ferrule which causes heating in the coil and failure.
And of course who knows what kind of weak spark you get when that thing is loose...hopefully a gentle turn with a pair of pliers will keep them in place.