The International Cessna^® 170 Association

I have a question on my cht probe which is on the Lower one 1 cylinder and is attached with the circular gasket. I believe mine has been on for at least ten years without beening replaced. My concern is that the spark plug is not going to seat properly. How many times can you take a spark plug out and replace it without a new crush washer. I use new ones or the heat treated ones when I replace the other plugs. It seems to be working fine but it would be nice to know how the rest of you handle this. It is an 0-300-A. My IA says if it is working don't worry about it.

The copper spark plug gaskets are designed to transfer heat from the plug to the cylinder. If your probe is in good condition, not bent or deeply malformed, and clean from corrosion it should be fine to reuse.
It should be on the No. 2 cylinder, not the No. 1. (Cylinders are numbered on Continental engines starting at the one closest to the co-pilot position (right/rear) as No. 1, then the one closest to the pilot is No. 2, and so on. All those on the right side of the airplane are numbered from rear to front as 1,3,5, and those on the left side from rear to front as 2,4,6.