CAUTION WARNING WARNING TM 10-3930-643-10 3-5. TROUBLESHOOTING PROCEDURES. M A L F U N C T I ON TEST    OR    INSPECTION CORRECTIVE ACTION 1. ENGINE    FAILS    TO    CRANK,    OR    CRANKS    SLOWLY    WHEN    STARTER    SWITCH    IS    ACTIVATED. After     every     30     seconds     of     cranking,     allow     two     minutes for     the     starter     motor     to     cool. Step    1. Check    to    see    if    master disconnect     switch     is     on. S/N     2000     and     below     -     If     off, insert    key,    and    turn    switch    to right. S/N     2001     and     above     -     If     off, turn    switch    to    right. CHEMICAL     BURN     HAZARD Sulfuric    acid    contained    in    batteries    can    cause    severe chemical     burns     if     not     handled     properly. FLAMMABLE Battery     gases     are     flammable     and     can     explode     if     not handled     properly. Step    2. Check    battery    electrolyte level.    Refer    to    paragraph 3-6. If    low, refer to organizational maintenance. 3 -4