The EY3 throttle is probably not a direct drop-in replacement for the QS-S4 (or other throttles) but, by all accounts you can make it work (and others have).
To replace the QS-S4 (or similar with the) Minimotors EY3 throttle, you will need to:
- Construct a wiring harness to go from the EY3 connector to the 5- or 6-pin barrel-style connector on your Mantis.
- Make sure the new EY3 throttle has the right P-settings configured for your Mantis. You can find the generic ones for EY3 here.
However, in cruising Alibaba, I did recently see some MM EY3 throttles that have the 6-pin plug-and-play style connector, so you might get lucky:
If I were you, I’d wait till you get your Mantis to see what connector it ends up having (or request the pinout for it from whoever you bought it from – hopefully they can help).
Once you know the pinout/connector type of your Mantis, I’d shop around and see if you can’t lucky with an EY3 throttle with the water-proof plug-and-play style connectors that will most likely come on your new scooter.