The motor was running fine. While cruising along at about 80% throttle it suddenly dropped the RPMS by at least 50%. I throttled back and it ran OK for maybe 10 seconds until I tried throttling back up. It sputtered a bit and shut down completely and would not start. Got in on my spare. Back in the garage there was no spark on either cylinder. I've never had an issue with the motor. I'm considering buying a new power pack, given that neither cylinder has spark. Is this a reasonable bet?