Keg poppets

[Beerbuddha]

Does anyone else have issues with poppet valves for cornelius kegs ?
I have bought some spares and issue i'm finding is when i go to pressurize keg the gas post will not let c02 in.
If i lower pressure enough it sometimes lets pressure into keg or does not. No issue with originals ever no matter the pressure.
Could it be an issue with the spring in the poppet not being able to press against the valve in post ?

[Will_D]

The poppet should be slightly proud of the body. If its not its a fault in the keg.

If its proud then its a fault of the coupler!

[Sorcerers Apprentice]

There are a number of different brands of Corny kegs as we call them, One of course is Cornelius and others like Spartans etc they have different posts and poppets so by rights you should replace like with like. I bought a few universal poppets and they worked with some of my kegs and leaked with others.
http://www.chicompany.net/index.php?main_page=index&cPath=3_14
http://www.cornykeg.com/resources/corny-keg-tips/identify-keg/

[Qs]

That explains why I can't interchange the poppets on my kegs then.