Hi Guys, I need a bit of help. Just bought of some one Engel Lafayette, no radio,but receiver only, the motor shaft seems a bit stiff when turning by hand,don't think it is normal,I can't check it under power until I find 75mgh, futaba or jr I would like to open the aft, compartment to check the motor,but can't figure out how.Does any one have the building instructions,would greatly appreciate and don't mind to pay. Thanks.