help eletronic problem

[matt salas]

after i took out my crawler from the mud run it started to jerk what can cause that

[jvella]

Did you waterproofed the electronics?

[Rook82]

Could be the electronics got wet from the mud like Jvella said. Or it could be crud in the motor. There are brushes in the motor that ride in slots (top of the motor, opposite side of where the pin comes out that the pinion gear is attached). If dirt or silt gets in it then the brushes get hung up and may not be able to contact the motor internals (communicator). You will get jerky movement or no movement from this. Best option and what I always do after a mud run is tear down the motor and clean it out. You can pick up some rc motor spray to clean on the go. Comes in bottles like spray paint and is similar to brake cleaner for a full size car (I wouldn't use brake cleaner on the rc).

The other thing is the transmission or axles may have filled with crud and are getting locked up. Mud is hard on RC's and a lot of things need to be done first to run in it. There are tons of threads on here about waterproofing (needs to be done for mud too, not just for driving in streams, etc).