55 Johnson CD12 high and low speed valves

[iron]

Hello, I am in the process of rebuilding an ole Johnson CD12 5.5hp and after taking the high and low needles out I noticed that they are starting to strip. ( possibly the previous owner was a little over zealous in his adjustments 30 years ago) Does anyone know the thread size is so I can clean up the threads? 1/4 by what?

 

[F_R]

Re: 55 Johnson CD12 high and low speed valves

I used to know, but have forgotten. For sure, it is not a common size that you will find at the hardware store. A thread gage will tell.

 

[F_R]

Re: 55 Johnson CD12 high and low speed valves

1/4-40 comes to mind (with a question mark). McMaster Carr lists taps with 1/4-18, 20, 24, 27, 28, 32, 36, 40, 48, 56, and 80. Wow. Didn't know there were so many