96 xp misfiring

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biggal76

biggal76

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Just got this machine but had a cascade of problems since purchase. Machine was running good. Then started misfiring. I'd had a leaky VTS boot that caused the hull to fill with water. The hull had water in it for a few hours at most. I didn't realize that the rear electric box wasn't sealed and it was full of water for a long time before I noticed and dried it- probably a week or two. A couple weeks later, the starter solenoid went (likely due to being submerged in water and then corroding). I replaced it and it solved my problem. About a week later it started misfiring. It seems like an electrical misfire. I assumed it was the coil, especially since it had been submerged in the electric box, so after ruling out spark plugs as the issue, I replaced the coil but that did not solve the problem. It seems to get worse the more it runs (I rode it a little bit like that and it worsened and now as I'm running it to troubleshoot, it's getting even worse).
I've been reading on the forum. Seems like rectifier is next likely suspect. Since I have no tach, I am just assuming, but when I rev it, I'm getting about 13.2V. I've read anything under 13.5V means replace rectifier, but I'm not positive what RPM I was revving and it was misfiring as it revved. What else can I do with a multimeter to pinpoint my problem? I don't want to wait a week to get a rectifier, spend time installing it, and find out that isn't the problem.
 
Disconnect the red wire coming off the rectifier and see if the problem goes away. Just be aware that as long as the red wire is disconnected the battery won't be charging so don't run too far with it disconnected
 
Yep, runs good with red wire unplugged. Thanks for the help. When I install new one, are the 3 yellow wires interchangeable-doesn't matter which yellow plugs into which?
 
Got the part (used on Ebay). Still doing the same thing. When I unplug red wire, it works fine. Is there anything else it can be or did they send me a bad part? Is there something else on the machine that could be blowing the rectifiers? Also, I only rode for about 1 minute with red wire unplugged and it completely killed my brand new battery. Does that make sense or do I also have a defective new battery? Electrical gremlins suck!!!!!
 
Don't buy a used one on ebay or anywhere else. Get a new one! Matt Braley has had good luck with the cheap new ones on ebay, just make sure it is shipping direct from the USA not overseas.

You should be able to run a few hours until the battery dies. Most of the race skis and performance standups run what is called a total loss system so they don't charge and can still get an hour or two without recharging.
 
mikidymac said:
Don't buy a used one on ebay or anywhere else. Get a new one! Matt Braley has had good luck with the cheap new ones on ebay, just make sure it is shipping direct from the USA not overseas.

You should be able to run a few hours until the battery dies. Most of the race skis and performance standups run what is called a total loss system so they don't charge and can still get an hour or two without recharging.
Click to expand...
So I assume you think I just got a bad used part on Ebay and the problem is definitely the voltage regulator?
Regarding used vs new Chinese regulators: I had assumed the opposite as the aftermarket starters are horrible and used OEM are much better. I'll follow your advice on it and buy a new one. I don't understand how the battery died like that. It wasn't a cheap battery; Motocross by Yuasa-brand new.
 
Yes, I think you were sold a bad used regulator.

The smoking gun is pulling the red wire makes it run fine.

Matt knows his stuff so I trust him on the new eBay ones.
 
Went through the same drill replaced rectifier with a sea doo part, unplugged red wire still bogs. Seems to missfire after 1/4 throttle.gas lines done, have done all the " common" issues with ski. Daughter drove seemed to clear was ok then boom, died out, Does restart will idle does not take power. Lost please help!
 
Dave G. said:
Went through the same drill replaced rectifier with a sea doo part, unplugged red wire still bogs. Seems to missfire after 1/4 throttle.gas lines done, have done all the " common" issues with ski. Daughter drove seemed to clear was ok then boom, died out, Does restart will idle does not take power. Lost please help!
Click to expand...
Coil? Easy to access in rear box and test with ohm meter. Tells how in service manual.
 
Bought new Ebay regulator. Still same issue. Still runs fine when red wire unplugged and runs terrible with it plugged in. What else would cause this? I've already bought 2 voltage regulators and a coil and haven't been able to ride for 3 weeks.
 
Measure for AC voltage while its running. There should be none.
Possibly bad stator. Or ground connections between the engine, coil, and battery.


Or bad positive wire.

That regulator will shut off unless it detects power. So if you have a bad fuse between the battery and the regulator then the regulator would be kicking in and out.


Also a weak cdi would do this. As you give it more voltage it breaks down.
 
Where would I put + lead to check for AC voltage? I'll double check wires (already did all connections through the rear electric box and on the battery) but my money is on CDI. If CDI, ski would run fine with red wire unplugged from voltage regulator?
 
Negative on engine.
Positive on battery first.
Then on the red wire while its connected and running.
Then measure for DC volts between engine and batt negative.then from engine and ground plate in the grey box.
 
Just ruled out anything in the entire front electric box (MPEM, CDI, rectifier, fuses, relay, etc) by hooking up a whole other box. Same symptoms. Seems only thing it can be is stator or stator pickup or a connection between the pickup and the electric box.

Not sure if this gives any clues, but it also runs fine when all 4 rectifier wires are hooked up and the rectifier isn't screwed down against the ground plate.

Further thoughts? Any easy way to test the stator or pickup without taking flywheel cover off?
 
Got flywheel cover off and out. Tried testing stator. none of the yellow wires short to ground when I test them with multimeter. All yellow wires short together, which I think is correct. I can't get any resistance readings at all as I thought I was supposed according to service manual. Stator and pickup are quite clean and corrosion free. How can I test it? I think stator is the only thing that can possibly be causing my problem so I'm tempted to just buy one and put it in but I'd feel better if there was a way I can test it
 
What about the ground wire going from the plate to the stator.? The only connection the regulator has to the engine is through that wire. 0 ohms as is doesn't mean it stays that way while running.
Check for voltage between the engine and the plate in the grey box. There should be none. Or very low millivolts.
To test the stator you need a meter that measures below an ohm.
I have had a pickup do the same as what your describing but I don't think that is the case here.
 
Don't the 3 yellow wires from the regulator go directly to the stator as well? The plate in the box is definitely grounded... I tested that.
 
The 3 wires go to the regulator but there is also a black ground wire that is going through the same plug to where the stator mounts to the cover.
I cant remember but I thought the stator had 4 wires because the ground wire was crimped onto the stator body.
 
Last edited:
Yes. I have had one bad pickup cause good bottom end but misfire on top end. But only because it was covered in metal shavings from the starter over time. The pickup was still bad though.
 
Guess thats what ill try next. Wish id just done it with stator. That’s the only electric component left so it should fix it
 
It's not the pickup. original was very clean and so was the one I replaced it with
It's not the stator. Same conditions as the pickup.
It's not the voltage regulator (i've tried 6 replacements)
It's not the CDI- tried one out of a very clean almost like-new electric box
I doubt it's the coil. I bought a used OEM on Ebay and put it on without improvement
I tried a different MPEM so doubt it's that.
There are no blown fuses
It always works well when I unplug the red wire or ground from the voltage regulator. Also works fine with entire voltage regulator removed.
I have no idea what else it could possibly be. No one else seems to either. I have no idea where to go from here. What connectors could be bad that would cause this?
 
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