The green machine model hmc s25h is the same shindaiwa T25/S25. 1] try a new spark plug,2]check if the Switch is working properly,3]CLEAN!the Coil/flywheel and check the gap,if no spark,try another Coil [good one],4] try another Unit (little box under the Carburetor)check all connections from the Coil/Unit/Switch if no spark let me know how much you want for the trimmer :-) good luck.
Alvin, July 2009
