Just as Jaz said, failsafe units "remember" the value of the signal (not brake position...) and if you have a reversed setup (linkages, reverse switch) youŽll get a reversed failsafe function (full throttle)

Same happened to me with several cars and 2.4GHz receivers. My 1/8 bike feature reversed 2nd channel due to the Ezrun esc installed, and one of my buggies have a reversed carb too.

I always mark a spot on the side of those receivers that have been bound for reversed throttle systems and do keep in mind when I need a receiver for a particular car/bike/esc.

I check the setup of each memory of my radio (I own an M11) and install the matching receiver to throttle normal/reversed (no spot/spot).

In case of no memory radio or no extra receivers, get an extra failsafe (cheapo compared with an extra receiver...) and mark that way in order to see which one you need to use for any car you got.

Hope this helps.

Cesar.