low battery causes......

joe padilla · Joined: 16 Oct 2001 Posts: 101

can you guys tell me what problems that might occur with my battery not being fully charged-- it starts just fine but----

Chris Cumming · Posted: Mon Aug 12, 2002 8:03 pm Post subject: low battery causes......

One symptom would be misfiring/poor running at medium-to-high RPMs. This happened to my friend's kart last race and it was solved by a new battery, after trying all the regular jetting changes.

Nick Weil · Posted: Tue Aug 13, 2002 5:42 am Post subject: low battery causes......

Rotax is a total loss ignition system. This means that your spark for ignition is supplied directly from your battery. If your battery is not charged well enough, it will not provide the necessary spark at higher RPM's.

You may notice a voltage 'spiking' pattern. This would feel like:

1. Kart revs normally right up to whatever maximum RPM the battery can sustain. For arguements sake, let's say 11,900(but this will vary).
2. Then at 11,900 it will literally die, your RPM gauge may even read 0 momentarily.
3. Then suddenly the kart will rev back to life and attain that 11,900 or maybe slightly less.
4. This will continue until eventually you drain the battery enough that the top RPM will no longer be near the 11,900 RPM. At this point you are damaging the battery, but it still may be salvagable.

Hope this helps...

Nick

[ August 13, 2002: Message edited by: Nick Weil ]

joe padilla · Joined: 16 Oct 2001 Posts: 101

hey thanks for the replys- i thought might be the problem but i did not know where to look in the past posts- i did not know it would hurt the battery it self, also would the low battery make it run bad from about 2500 rpm's to about 6000 rpm's ????

Chris Bradley · Joined: 19 Aug 2002 Posts: 10 Location: Vancouver, BC

I have a similar problem in the lower RPM's until the exhaust valve kicks in... and isn't the battery. (the aforementioned person who replaced their battery last race was me)

Nick Weil · Posted: Mon Aug 19, 2002 12:12 pm Post subject: low battery causes......

Typicaly the low battery is going to affect top end because of the voltage required not being available. I suppose at some point in the lower RPM's there is a possibility of the spark not being available, but I would think it unlikely. Especially if the motor is capable of revving past those 'trouble' RPM areas. If you are having RPM problems in the lower ranges you may want to consider:

Air mixture screw (try setting it all the way in, and then back it out two full turns)
Needle settings (if it is bogging lower the needle by raising the clip setting)
Change your spark plug, it may be fouled

No more secrets today...

Nick