C15 Sticking exhaust valve or is it something else.

[Singleton]

Hi
My C15 has a Sticking exhaust valve I think.
When turning the engine over after a few turns the exhaust valve sticks fast and the only way I can release it is by loosing the tappet.
So in my novice voice I am asking is it the new exhaust valve or something else.
thanks

[JulianS]

The only way is to strip the ead off and check.

Assuming the springs and collars are correctly assembled is the valve bent or too tight in the guide, if the engine has been run with new valve and presume new guide is there a build up of carbon on either or both?

[Singleton]

Brand new collar and springs and brand new valve.
The Rocker box has not really been touched .