richard
Owner/Pilot
I had a misfire in my 161 Warrior that just would not clear today. I aborted the flight (at run-up) and returned to parking. When I pulled the plugs for the right mag, 3 looked great and 1 - not so much.
Checking the resistance, the best one was 120k ohms. The others were essentially open. I unscrewed the cap that holds the spring and resistive carbon pile. 2 showed internal damage from arcing and heat.
The plugs themselves were essentially 0 ohms without the resistor. The resistors by themselves were about the same as the original measurements. I understand new plugs should be about 4k ohms.
I bought my plugs new and installed them about 12 years ago and put 900 hours on them, and never thought to check their resistance. I won't do that again. Every time the plugs come out, they're getting checked - even if they look good and seem to be running fine.
I'll install new plugs this weekend and report back.
Checking the resistance, the best one was 120k ohms. The others were essentially open. I unscrewed the cap that holds the spring and resistive carbon pile. 2 showed internal damage from arcing and heat.
The plugs themselves were essentially 0 ohms without the resistor. The resistors by themselves were about the same as the original measurements. I understand new plugs should be about 4k ohms.
I bought my plugs new and installed them about 12 years ago and put 900 hours on them, and never thought to check their resistance. I won't do that again. Every time the plugs come out, they're getting checked - even if they look good and seem to be running fine.
I'll install new plugs this weekend and report back.
