I have a 1990 fourtrax 300 with new CDI and small but working battery. It turns over strong but only tries to crank with charger hooked up at 40amps. IT only has spark for one revolution without jumper box. Runs fine on jumper box. Stator could be problem but not 100% sure. Also may be rectifier but finding a six wire aftermarket replacement has been difficult. Could it be something else? Looked service manual over but still not sure what to purchase. Thanks for any help.