A timing light will also tell you if it is getting spark on both plugs. These little engines are real sensitive to ignition timing and timing is dependent on point gap. On the side of the points plate is two marks about 1/4 inch apart. Connect the timing light to any 12 volt battery and clip the reluctor on a plug wire and start the motor. Shine the light at the two marks and the mark on the flywheel should be inbetween the two marks on the plate. Adjust the point gap for that culinder intil you make that happen. Then do the same for the other cylinder. Adjust engine sync next on the throttle cam attached to the points plate is a mark you want the carb to just begin to open as the mark on the cam passes center of the roller. To adjust sync loosen the two bolts holding the cam on and adjust the cam position to make that happen. You can add a kill button for real easy restarts. With the flywheel off add two wires one to each set of points. If necessary drill a hole in the plate and install a grommet to put the wires through and run them to a kill switch. That should be a one pull start motor are you installing the coils properly? You must pull the plate then pust the plug wire in fully then push the boot up tight. Install the coil and use a straight edge to square the front of the laminate to the machined edge of the boss the coil sits on. Did you install new points and condensers? If not now would be the time and be sure to clean the points with acetone or lawuer thinner as well as your feeler guages a little skin oil will damage new points in no time.