compression issue

2002 wr426 , something is a wrong, I can turn over the motor without using the decompression lever. what is the chance that it is a stuck valve and if so solutions?

It's one of:

Stuck valve

Leaky valve seat

Broken decomp << most likely

how does one tell if the decomp is broken? I am able to pull in the lever and see the switch move under tension.

At least one of the valves has zeroed out.  Meaning no clearance and loss of compression.  Time for a head rebuild.  

Actually, a zeroing valve usually does not mean no compression, just no start. 

A valve at zero generally does cause a loss of compression.  Usually, by the time they get in that condition, they go beyond zero, and you find them off the seat when the engine cools down.

You are right

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