i have finaly finished my mbx6 build and finaly got a day where i could have time to run in engine...got it started beautifuly first time rani it at 1/4 throttle stop start for a tank left to cool re-fill tank came to start again starter box not working

tested battery ok 12 volts through the switch surely after 1st time cannot be the motors it is a smd stater box supposedly quite a good one??