I would run the Falcon until it dies, there was a batch or two that were bad, no way of telling if ya got a bad one or not.
If it dies buy an RCEXEL or CH ignition, you will have to re-time it because they are different than falcon
The only difference between the 115 and 116 is the carb read block, which is a little heavier unless you have the latest version which is not aluminum. The 115 has always been 116cc+ engine from the start.