400ex cutting out

[trx416m]

I raced my 400ex in a harescramble yesterday and 1/4 of the way through the race it would shut off and not start back up now im pretty sure its the kill switch not the tether or the key bc i took it apart and it had a lil mud and water in it, the spark plug was perfect golden brown color and the air filter was clean it had gas and everything. any suggetions are appreciated.

[cals400ex]

make sure the mainjet didnt' fall out or the needle assembly didn't come out.

[trx416m]

it started up fine this morning. i think that the water dried in the kill switch but if anyone else has any suggestion on wat might have happend they would b nice also do the pro design kill switches usually cut out wen they get muddy or watery?? when it did cut out if i fiddled with the kill switches and waited like 10 min it would start back up and drive strong for like 100 more yards then would shut off and after about the third time it wouldnt start back up
but again it did start fine this morning