I know all of myRryobi's (4 and 2 stroke) will show a spark with the plug out but won't fire by hand. Then I tried a 14.4volt cordless drill and it wouldn't fire at that speed (400-500rpm?). Now I always use an electric starter and just burned one up by leaving it on to long. I ordered another one and built a belt-drive similar to Miller's Persuader. 2.2:1 reduction. I plan to run it on about 16volts. Should provide ample torque.