Re: 4 cyl engine 2 cyl. no fire
Look up the wiring diaghram and see if the overheat sensor is connected to the powerpack. If so, you have the SLOW systems that kills the spark to 1/2 the motor, if it overheats. You should be able to disconnect the overheat sensor and see if spark returns.
If that isn't it, get a manual, and troubleshoot the powerpack in question.