bad stator?

RoostinRyan · Mar 3, 2018

I have a new issue going on with my 12 800 RMK. Today after letting it warm up while getting ready I rode to the trail from the snopark and I kinda noticed that it didn't seem to be running smoothly. The longer I ran it the worse it got. To a point where it smelled badly of fuel and had barely enough power to get over the berm. I swapped out plugs and made no change. The plugs looked soaked in unburnt gas and oil. Especially the mag side, which didn't look like it was even firing on the way back to the truck. Once I got back the thing would even idle it was running rough and missing. I let it sit for a while and cool off and started it back up and it ran normal. The lights and gauges aren't flickering or anything. No checked engine light. Seems directly related to heat. Some of the posts Ive found makes it sound like the Voltage regulator but seems like they've also had issues with their gauges and lights flickering. Anybody have any input?

Hansen13 · Mar 3, 2018

Search on here or Google there is a spec for the stator. Below the oil tank there's a pouch of wiring and there'll be 3 plugs that come from the stator. You can test each of those to make sure they're in spec. With an ohmmeter.

Also could be you have an injector leaking, too much fuel dumping into one side if you're not WOT all the time.

I just replaced a bad Voltage Regulator, didn't affect the sled minus blowing headlights and one of my hand warmers. Sled ran perfectly. Replaced the VR and all was good.

One more thing if you believe it is heat related check your wiring anywhere might be rubbed through or shorting out. Mine had some shorting out tail light wires and once they got warm the sled would quit and wouldn't fire till it cooled down. Dumb, but it fixed that issue.

Your coils could also be getting heat soaked. I don't know the test for them as I'm dealing with that right now. I was able to put snow on mine today and roe it all the way out no issues so I assume they're NFG haha.

RoostinRyan · Mar 3, 2018

Hansen13 said:
Search on here or Google there is a spec for the stator. Below the oil tank there's a pouch of wiring and there'll be 3 plugs that come from the stator. You can test each of those to make sure they're in spec. With an ohmmeter.

Also could be you have an injector leaking, too much fuel dumping into one side if you're not WOT all the time.

I just replaced a bad Voltage Regulator, didn't affect the sled minus blowing headlights and one of my hand warmers. Sled ran perfectly. Replaced the VR and all was good.

One more thing if you believe it is heat related check your wiring anywhere might be rubbed through or shorting out. Mine had some shorting out tail light wires and once they got warm the sled would quit and wouldn't fire till it cooled down. Dumb, but it fixed that issue.

Your coils could also be getting heat soaked. I don't know the test for them as I'm dealing with that right now. I was able to put snow on mine today and roe it all the way out no issues so I assume they're NFG haha.

I did some testing and when it was missing was putting out 14.5v at the DC plug. Also checked both coils and both of them run on the mag side cylinder but neither on the clutch side. When I pulled the plugs after running, vapor was coming out of the clutch side cylinder so this one is the issue for sure. I'm waiting to get my compression tester back to rule that out. If it checks out im thinking it might be the injector on that side. I'll do a more thorough inspection of the wires to see if any are rubbed through. Seems fishy that it seems only one cylinder is going down.

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High Voltage · Mar 4, 2018

When my stator went bad the sled acted worse the more load that was added, like high beams/hand warmers turned to high. Taking ohm reading it looked ok, but there is no way to know for sure unless its put on a test bench. Good luck ?

RoostinRyan · Mar 4, 2018

High Voltage said:
When my stator went bad the sled acted worse the more load that was added, like high beams/hand warmers turned to high. Taking ohm reading it looked ok, but there is no way to know for sure unless its put on a test bench. Good luck

I'm thinking this is a different issue as it seems load doesn't affect it. One cylinder isn't firing at all.

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XCaSSAULT · Mar 4, 2018

For one cylinder to be down I’d think compression (which u said) or ignition coil, or injector.

Test both plugs and compare spark.

Small amount of gas in suspect side. If it runs good for 20sec or so then it’s prolly fuel related.

Crank coulda possibly went out of phase but I’d think it would at least run. (Long shot)

Does it still only do it when it’s hot? Or all the time now?

RoostinRyan · Mar 4, 2018

XCaSSAULT said:
For one cylinder to be down I’d think compression (which u said) or ignition coil, or injector.

Test both plugs and compare spark.

Small amount of gas in suspect side. If it runs good for 20sec or so then it’s prolly fuel related.

Crank coulda possibly went out of phase but I’d think it would at least run. (Long shot)

Does it still only do it when it’s hot? Or all the time now?

It only does it when it gets warm. Runs normal at first then you can slowly notice the cylinder fading out. Spark is the same in both coils and both coils will run on the mag side but neither will work on the clutch side. (running on one cylinder). When you pull the plugs the clutch side will have fuel vapor coming out of the hole. Also it just reeks of raw fuel.

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XCaSSAULT · Mar 4, 2018

Starting to sound like crank position sensor. How many miles on it? Maybe replace stator just to rule it out and even if it’s not the cause you know it’s good for a long time

I hate trying to test these things as temp can affect readings and you really need a $400 plus ohm meter for better accuracy.

I’ve read some posts about wires coming loose near the flywheel and causing a problem. Shouldn’t be to hard to pop the recoil off and have a look.

RoostinRyan · Mar 4, 2018

XCaSSAULT said:
Starting to sound like crank position sensor. How many miles on it? Maybe replace stator just to rule it out and even if it’s not the cause you know it’s good for a long time

I hate trying to test these things as temp can affect readings and you really need a $400 plus ohm meter for better accuracy.

I’ve read some posts about wires coming loose near the flywheel and causing a problem. Shouldn’t be to hard to pop the recoil off and have a look.

Just out of curiosity, can you meg stators out like you would the windings in a motor? I have a fluke megger for megging motors at work. Stators aren't super expensive or anything but would be nice to pinpoint it. I'm in the middle of buying a house so trying not to spend too much of my down payment on this thing. Haha.

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High Voltage · Mar 4, 2018

A megger is for testing the insulation, windings to ground. I don’t think that will tell you much in your case.

RoostinRyan · Mar 4, 2018

High Voltage said:
A megger is for testing the insulation, windings to ground. I don’t think that will tell you much in your case.

Yeah that makes sense. I feel like if it were the stator I would be having lighting issues and weak spark. Does that sound like a reasonable assumption? I guess I'll check the compression tomorrow and report what I get.

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RoostinRyan · Mar 5, 2018

Compression test results:
pto = 137 psi mag = 139

The concerning thing is I ran it for about 40 minutes up to 155 degree engine temp and it didn't miss a beat. Yesterday, idling it for 10 minutes resulted in it missing on the pto side. Any ideas? I'm gonna search for loose connections. I have to store it outside so maybe something got wet?

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peaceofwork · Mar 5, 2018

Ryan did you try swaping the plug caps to opposite spark plugs? Then of course see if the wet side becomes the dry side of the motor?
It would be your lucky day if you just had to trim a 1/4 inch off a plug wire and put the boot back on.

RoostinRyan · Mar 5, 2018

peaceofwork said:
Ryan did you try swaping the plug caps to opposite spark plugs? Then of course see if the wet side becomes the dry side of the motor?
It would be your lucky day if you just had to trim a 1/4 inch off a plug wire and put the boot back on.

Not very lucky there. I tried swapping them and it was still the clutch side. I want able to recreate the problem today after running it a bunch. I went through the connections and found moisture in the injector harness plug. I dried it out and put some dielectric grease on it. Gonna try it again and see what happens. I hate not finding a definite answer.

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