I am looking for the part number for the green oring for part 99620701274
Number 27 oring is for the accordion piece on the tank. 99970736440
and Number 25 are 2 black orings for the other side.

 

I'm surprised you have the diagram but not the legend that goes along with it...

 

Im looking for the oring in the second picture

 

The one I listed is for #27 as you said. 25 is a different number...

 

That is the part number for this oring

 

Yes - that is what you asked for. If you want a different answer, you're going to have to change the question...

 

Thanks for helping me out. You may have misread my question

 

I'm debating whether or not to try to remove this oring and measure it

 

Perhaps... You can always re-word it... #27 is the o-ring for part #26 which is the other side of the part that has #25 o-rings.

 

Just realized these are my fingers on the picture above ;-) Yes I took that picture and replace this valve in August 2010. Let me check if I still got that part and I will measure the o-ring...
...I got the o-ring in my hand...The measurement are:

 

Wow, I'm very greatful. I did not want to pull it off in case I damaged it. Thanks!

 

Happy to help! Good luck with your project....