Weak Battery? Or no Charging?

[Austrian Rotax]

hi everyone, still I can't get away from issues with my 96xp one after the other it feels like. now I think its my battery or alternator (I dont know how the charging system works in this doo) Im not sure though, the ski goes from 0 to full throttle no problem with no hesitation whatsoever then once I get to around 45-50 mph it is revving around 6500rpm then after about 10 seconds the RPMs start slowly droping and droping until I let off throttle. Also every time I go above idle on the water the battery light comes on in the dash once I let off throttle the battery light immeditely turns off. it has no hesitatations whatsoever when accelerating just when it gets to WOT the RPMs drop. Carbs and fuel lines done last year.

so I started my trip on the water with my battery sitting at around 12.6 volts and when I put the ski back on trailer to head home it was at 11.85volts 30mins later. I just find it hard to believe the battery is bad since the ski cranks over like it has a new battery in it (battery hasnt been replaced for 1 year now). As a side note the ski did take more cranking then normal to start it. Usually it starts within about half a second of cranking last week. this weekend it took 15 seconds of cranking to start.

Sorry about long story, I just dont want to replace the battery only to find it was my charging system any troubleshooting I can do?

Thanks for any suggestions.

 

[Coastiejoe]

Easy enough to isolate this out. What is the voltage before the ski is started? What is it once it is started? What is it when you rev the engine up a bit?

 

[Austrian Rotax]

Ok ill try this out but I will have to do this while the ski is on the lake. For some reason when I had the ski on the hose last month the water pressure cracked my exhaust manifold which I repaired with J.B weld. And I did follow the right procedure with engine on, water on, water off, engine off.

I dont want to crack anything else in my engine so ill have to try to use my meter while the ski is on the water and see how the voltage goes. I dont think I will be able to test it when it when I rev it up a bit.....id be the laughing stock for everyone at the boat launch while I fly off lol. but I think I could test it at idle without trouble.

How long can I run it without overheating it (no water)?

is the charging system on this ski a common issue or is it most likely battery? Also where is the red rectifier wire? id like to check on its connection.

Thanks for the help

 

[Coastiejoe]

How long can I run it without overheating it (no water)?

is the charging system on this ski a common issue or is it most likely battery? Also where is the red rectifier wire? id like to check on its connection.

Thanks for the help

The MAX is 1 minutes run time when not on a body of water. The real issue is not overheating the engine, but damaging the carbon seal. I need to look up where your rectifier is mounted, don't recall off hand. The rectifiers fail often. And in two different ways. It can fail to charge as well as fail by producing A/C volts. When it does this, it screws with the MPEM and the ski runs in a few weird ways. Mostly affects the high end RPM capabilities.

 

[manolocross]

With zero water 15 seconds MAXIMUM!

 

[Austrian Rotax]

hi guys,

There is a black wire coming from my black electrical box (near the battery) that is not connected. Could that be the reason? Im confused since I always hear there is only supposed to be 2 black ground wires on the negative terminal right? i have two black ground wires on the neg terminal already but one is coming from my VTS module.

Also yes the battery I tested when idleling doesnt go above 11.9V and when cranking the battery drops to 10.7 volts.....im surprised it still cranks over and starts.

Is the rectifier repairable?

Thanks for the help.

 

[1983]

That black wire coming from electrical box right next to battery needs to be connected to negative terminal with negative ground cable on the battery.

The wire coming from your VTS that is connected to the negative batt terminal....? Take some pics.

Rob

 

[scrisp]

If the black wire from the rear electronic box is hanging loose, the engine won't run at all. It is the ground for the ignition system. Mine was off and I chased my tail for 3 days wondering why the engine would not run, spit, or sputter, when it had before I opened the box. I had missed the wire hanging there, and as soon as I connected it to the negative battery terminal, viola, it started right up.

The VTS should not be connected to the negative terminal, it should just be connected in the wiring harness. The only wires that should be on the negative terminal (at least when it was built) are the one that I mentioned above, and the negative battery cable to the starter.

 

[scrisp]

hi guys,

There is a black wire coming from my black electrical box (near the battery) that is not connected. Could that be the reason? Im confused since I always hear there is only supposed to be 2 black ground wires on the negative terminal right? i have two black ground wires on the neg terminal already but one is coming from my VTS module.

Also yes the battery I tested when idleling doesnt go above 11.9V and when cranking the battery drops to 10.7 volts.....im surprised it still cranks over and starts.

Is the rectifier repairable?

Thanks for the help.

I just replaced a rectifier in my SPX and it sounds a lot like the problem that you're having. I could charge the battery and take it out for an hour or so, but then it would start misfiring and when I would bring it in the dock and shut it off, it would not restart, the battery would be drained. The way that we checked mine was to start it, take a voltage reading, then rev it to 4500 rpm, and recheck the voltage. If it's over a certain voltage (14.8 I think) then it indicates a rectifier. Mine was at 20+ volts!! I bought a rectifier form EBay for something like $15, and it took all of 5 minutes to replace, and she runs like a champ now.

I don't see them as being repairable, it's a circuit board encased in a polymer substance, inside a metal frame.

 

[Austrian Rotax]

well here is the picture of the wire that is not connected, yet the ski still runs. Also I found out awhile ago and forgot to mention I have an aftermarket VTS with a red wire and fuse holder going to the positive terminal of battery and a black wire going to negative terminal of battery

I hope these pics are good enough. Also I know this is a bit off topic but about 1 month ago I suspected my oil injection wasnt working, and im still burning off 32:1 premix in my tank so if my oil injection is working right and with the premix could that be fouling my plugs? I always thought when a plug fouls the engine will stop and not start at all so im not sure about that.

The aligator clip there is just my 1.0A charger for battery

Thank you.

 

[Coastiejoe]

Also yes the battery I tested when idleling doesnt go above 11.9V and when cranking the battery drops to 10.7 volts.....im surprised it still cranks over and starts.

Is the rectifier repairable?

Thanks for the help.

The rectifier is not repairable. And I am also surprised it cranked over worth a darn...

 

[1983]

That black wire leaving the sealed electrical box must be connected to the negative battery terminal at battery.

I would fully remove any VTS electrical connections from battery or any power connection on ski, then diagnose all drivability issues, repair them. Then mess with VTS at a later date.

 

[Austrian Rotax]

Well finally had a chance to go to the bay, battery charging great now with that wire connected.
Thanks for all the help

 

[1983]

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