YTM 200 Decompression cable issue

[Thunderjet1]

I have a 1984 Trimoto 200. The decompression assembly to recoil is not hooked up. If I manually pull on decomp cable and try to pull recoil to start it, it wont start. It will start if decomp is closed. Why is that? Also, can I put a 225 dx manual decomp selector on it and get rid of the cable assembly?

thanks