Rotax 460 no spark but kinda?

not sure the year just trying to get the engine going. Replced lighting and ignition coils and no spark through the plug. BUT i took the spark plug boots off and just for fun i hooked up a 110 circuit tester for electrical outlets just has 2 wires that connect to a light bulb and. 1 end to the plug wire and 1 end grounded on the engine and it lights up the same a plug would. But it must not have enough to arc the plug. What else could be wrong??? absolutey anything would help