Diagnosis help

andy graham · Posted: Mon Sep 03, 2012 12:23 pm Post subject: Diagnosis help

bought this little crg with a sealed mini max for my son about a month ago...cleaned it up, changed out a flooded float and rebuilt the brakes and went to the track...Our first weekend was great -- the kart ran great, no problems either Saturday or sunday..kept the battery charged all week and started it every other day just to hear it run and excite my son. : )

Loaded up and went to the track yesterday...he was making laps for about an hour when I noticed his engine starting to sputter and pop, sometimes shutting down...he was able to refire it with the starting button and keep going until it died on him completely...now it's totally dead...the battery shows full charge and there is no reaction to pushing the starting button...totally dead...I figured fried cdi/coil...this morning I got a spare from a friend and tried that cdi/coil...same thing...connected the wires on the on/off switch to override the switch...nothing...did the same to the starter switch...nothing againa...traced the harness by hand and visual inspection looking for any rubbed wires or bad connections...again, nothing....any other suggestions?

Chris McGinley · Posted: Mon Sep 03, 2012 2:18 pm Post subject:

To be clear...when you push the starter button or jump the starter button wires you get nothing at all? As in, the starter doesn't try to do anything at all?

If that's the case, it sounds like you have a bad connection at the battery or a break in the harness. Or, the battery appears good but falls on its face under load; though I'd think you'd get something if that were the case.

Anyway...have you checked voltage at the switches? At the starter when you push the start button?

I'd suspect a wire broke somewhere based on your description, but please add some more details to diagnose further.
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Chris McGinley
Monster Raceworks
Rotax Masters
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andy graham · Posted: Mon Sep 03, 2012 4:59 pm Post subject:

swapped coil/cdi, harness and jumped switches...all nothing..charged battery to 13.1v...watched voltage meter as I hit the starter -- 11.2v as the start button is pushed...I think you nailed it...falls on it's face on ignition...but still absolutely nothing..turned the engine over with a 17mm wrench and still good stroke and regular compression, so not locked up or stuck...gonna get a battery and see what happens...found out the battery that was on the kart is three years old...I'm suspecting battery...****, what else could it be?

Chris McGinley · Posted: Mon Sep 03, 2012 5:49 pm Post subject:

Sounds like the battery is the only thing you didn't switch. The coil/CDI wouldn't affect the starter not engaging and turning over. If you jumped the harness for the switches, that rules those out. And, last, having replaced the harness (presumably with a known good one), then I think you've eliminated everything but the battery Smile

Borrow someone's if you want to be sure before dropping the money, but at 3 years old I'd bet you found your culprit.
_________________
Chris McGinley
Monster Raceworks
Rotax Masters
"Always stay one step ahead of the storm" - JZS
http://www.njkarting.org
http://www.btbsecurity.com

andy graham · Posted: Mon Sep 03, 2012 7:02 pm Post subject:

battery failed on attempted 1.8 amp charge....got to 85% and flashed "bad"....will pick up a new battery toomorrow

John Savage · Posted: Tue Sep 04, 2012 1:03 am Post subject:

Also check your starter, the bushes could of failed
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andy graham · Posted: Tue Sep 04, 2012 9:20 am Post subject:

picked up new battery at lunch, plugged it in, hit the start button and LIFE!!

Chris McGinley · Posted: Tue Sep 04, 2012 9:56 am Post subject: