Home Forums TaG Rotax Max Help bad day at the track

This topic contains 2 replies, has 2 voices, and was last updated by  Jack Cook 4 years, 2 months ago.

  • Author
  • #44047

    Jack Cook

    Today got to the track and found I had left the switch dead battery. Go to my back  up battery. This is a Max evo engine is running bad felt like it was going to die coming off the corners. Played with air screw, the clip position  changed jets . Could low volt cause this condition? I say this because my back up battery died when I left switch on again for a short period. I know Rotax are total loss system. How long should your battery Last?

  • #44054

    Nick Weil


    You are correct.  The Rotax is a total-loss ignition system.  If the voltage at any point gets much below 11.5v you will get insufficient power through the coil and intermittent spark as a result.  It should feel as if the motor is effectively, sputtering and shutting off, because that’s exactly what is occurring.  A fully-charged battery in most cases has the ability to run all day.  HOWEVER, if you are running the older Lead-Acid Sealed battery, if you take it below about 80% charge at any point you really end up damaging the cells long-term ability to ‘recharge’.  The Li-Ion battery is much more tolerant of this due to it’s internal makeup, but I still don’t recommend it.  The best bet is to have your battery on charge ANY time you aren’t on track, including sitting in the trailer, or at home in your shop or garage.

  • #44071

    Jack Cook

    Thank you. After yesterday when and a generator I will be charging and will pick up a second Li-Lon Battery text week. When I get to the to track this morning I have to change the carb set up back to what it was and start over

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