stock blaster clutches are tough to begin with, add in a cable that prolly needs cleaned and lubed and they get super tough.
remove the cable from both ends, with the bottom hanging down, i spray wd-40 into the upper end, numerous times until it runs out clean at the bottom, then tape a small funnel over the upper end and put some oil in it to allow it to run down thru,
working the cable back and forth during both of these procedures helps get it flowing