My wife and I have a small business of supplying parts for ECO Air Meters. You can see just about all the parts in our Ebay Stores (crspub.com) or on our website: www.crspub.com
One of the things I have done lately is to rewrite the ECO Model 90 Service Manual. I completely retyped it making it easier to read, used better illustrations again to make it earier to understand, eliminated many things that no longer applied and added "Jack's Tips" to better help you repair your unit.
I also included a section to explain how the ECO works (this was not in the original service manual) and also a place for you to look up what is wrong, so you can find a solution.
This manual is on both our Ebay Stores and on our website. I suggest you get a copy. I also am probably the only person in the country offering a repair service. This is also explained on our website.
We have a very large stock of parts and usually ship by the following day.
Hope this helps,
Author, Gas Pump Identification book, and Air Meter Identification book