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Stator Failure in 2022 SLSA RV12is

G

Giving Wings

Member
Seems we have a stator failure after 850 hours. Doesn't look like this is going to be a fun job to replace it. LEAF says 5K. Any thoughts on easier to just remove the engine or try to do it on the mount? Fortunately we have a second one to help carry the student load for the time being. I was just commenting how reliable they have been to someone that ask how they have been for training. Our Cessna's nickel and dime us constantly, but 5k? Ouch.
 
Giving Wings said:
Seems we have a stator failure after 850 hours. Doesn't look like this is going to be a fun job to replace it. LEAF says 5K. Any thoughts on easier to just remove the engine or try to do it on the mount? Fortunately we have a second one to help carry the student load for the time being. I was just commenting how reliable they have been to someone that ask how they have been for training. Our Cessna's nickel and dime us constantly, but 5k? Ouch.
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Have you looked into making a warranty claim?
I know it is probably beyond the calendar time limit but I think there has been a few failures contributed ti insufficient cooling (by the oil) that Rotax may be helping out with. It is worth a try.
 
Giving Wings said:
Seems we have a stator failure after 850 hours. Doesn't look like this is going to be a fun job to replace it. LEAF says 5K. Any thoughts on easier to just remove the engine or try to do it on the mount? Fortunately we have a second one to help carry the student load for the time being. I was just commenting how reliable they have been to someone that ask how they have been for training. Our Cessna's nickel and dime us constantly, but 5k? Ouch.
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If this is true, how could the designers be so negligent with a service item.

It sure makes a B&C starter look good at $900.00. And where Lycoming located it.

I sure hope they are wrong about this price....:eek: Stator?... oh!... nevermind. But, still a big deal.:(
 
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gasman said:
If this is true, how could the designers be so negligent with a service item.

It sure makes a B&C starter look good at $900.00. And where Lycoming located it.

I sure hope they are wrong about this price....:eek:
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I believe this concerns a generator stator, which the Rotax 912 has, not starter related. It’s at the very back of the engine, attached to the crank.
 

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Is it a starter or stator? Not knowing a Rotex I am confused.
If you are up in Traverse City and need an extra hand, let me know and I may be able to get away to help. I know nothing about Rotex but willing to help where I could.
 
rockwoodrv9 said:
Is it a starter or stator? Not knowing a Rotex I am confused.
If you are up in Traverse City and need an extra hand, let me know and I may be able to get away to help. I know nothing about Rotex but willing to help where I could.
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It's NOT the starter.
 
I fear that I'm approaching an early demise of my generator/stator as well. I have noticed a very slight decrease in output voltage at higher amps. For instance, when its outputting 15A, my voltage is now 13.6v whereas it used to be 13.7v when the engine was new. Additionally, I (sometimes) get fairly horrible radio noise for the first 15 minutes of a flight and then it clears up instantly on its own. I suspect there is some sort of arcing happening until oil gets splashed around a bit.

This Rotax Service Instruction talks about a new stator housing and a change of location of the oil spray nozzle. link The "new" stator oiler system is already on s/n 7705909 and higher.
 
Stator

Oh boy! I thought I was having a stator issue too. I wanted to vomit. However I made my plan to replace it.
Taking the motor off is the best way to do it.
However my issue was resolved and no stator needed.

Honestly if it truly is the stator and make sure 100%. I would pull the motor and sell it less the value of the stator and get a new motor.

Your at 800 hrs so the motor is still good to someone and you can use that money to pay for 1/2 the cost of a NEW one.

My plan is to list and sell my 912ULS by 800 hrs.

Just a thought, where you located?

Erich
 
Ok, well that doesn't sound too bad. Just need to conserve power and land ASAP. That's the one thing that spooks me about the 912iS. It relies on electricity to run it compared to ULS.

Does a failed stator mean both Gen A and B are not working? At one point, I knew all this from having watched some good YouTube videos that explain it but have since forgotten.
 
DanFrazer said:
What happens when the stator fails in an iS engine? Does it just mean you stop charging the battery?
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Well it means more than that. You lose generator power to the main bus so the battery will begin to discharge as it powers the items on the main bus.
 
DanFrazer said:
Ok, well that doesn't sound too bad. Just need to conserve power and land ASAP. That's the one thing that spooks me about the 912iS. It relies on electricity to run it compared to ULS.

Does a failed stator mean both Gen A and B are not working? At one point, I knew all this from having watched some good YouTube videos that explain it but have since forgotten.
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The stator failure we are talking about here affects the B generator. The A generator will continue to operate the engine.
 
DanFrazer said:
Ok, well that doesn't sound too bad. Just need to conserve power and land ASAP. That's the one thing that spooks me about the 912iS. It relies on electricity to run it compared to ULS.

Does a failed stator mean both Gen A and B are not working? At one point, I knew all this from having watched some good YouTube videos that explain it but have since forgotten.
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Both the iS and ULS have electronic ignition. The power draw of the injection system of the iS would add a draw, but electronic ignition is common to both engines. They both require electricity to run, just like your car.
No magnetos here, or there...

https://www.flyrotax.com/products/912-uls-s
 
Oh, you’re right. I think I confused it the iS fuel system. I think the ULS will continue to supply fuel even if the electric pump fails but the iS relies on power to get fuel.
 
DanFrazer said:
Oh, you’re right. I think I confused it the iS fuel system. I think the ULS will continue to supply fuel even if the electric pump fails but the iS relies on power to get fuel.
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True
But the primary or secondary power system on the 912iS also provides the power for the electric fuel pumps so no external power is needed as long as at least one of those systems is functioning.
 
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rcarsey said:
I fear that I'm approaching an early demise of my generator/stator as well. I have noticed a very slight decrease in output voltage at higher amps. For instance, when its outputting 15A, my voltage is now 13.6v whereas it used to be 13.7v when the engine was new. Additionally, I (sometimes) get fairly horrible radio noise for the first 15 minutes of a flight and then it clears up instantly on its own. I suspect there is some sort of arcing happening until oil gets splashed around a bit.

This Rotax Service Instruction talks about a new stator housing and a change of location of the oil spray nozzle. link The "new" stator oiler system is already on s/n 7705909 and higher.
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My problem presents as my Dynon HDX-1100 displaying Lanes A+B at 14.0 to 14.1V, and battery volts at 13.0 (Low, Yellow warning) and Generator Amps is 4. No faults, everything kept running. It apparently happened shortly before landing whilst doing pattern work.

I'm looking at replacing my generator/stator assembly.
 

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rcarsey said:
I fear that I'm approaching an early demise of my generator/stator as well. I have noticed a very slight decrease in output voltage at higher amps. For instance, when its outputting 15A, my voltage is now 13.6v whereas it used to be 13.7v when the engine was new. Additionally, I (sometimes) get fairly horrible radio noise for the first 15 minutes of a flight and then it clears up instantly on its own. I suspect there is some sort of arcing happening until oil gets splashed around a bit.

This Rotax Service Instruction talks about a new stator housing and a change of location of the oil spray nozzle. link The "new" stator oiler system is already on s/n 7705909 and higher.
Click to expand...

I should follow up to my own post, now that we're 2 years into the future.

My radio noise continued to get worse (more frequent) until I finally got a "Ignition 3/4" message on the G3X. Upon inspection, it turned out that the #4 lower spark plug boot had corrosion inside where the wire connects to the boot. Replaced the wire and boot and my noise (and G3x message) problem was solved. There were no indications of trouble with that boot until the message appeared -- and even then, I thought it might have been a fluke message, but it started to appear every flight. There was no obvious dielectric grease in the boots (on the wire side).

My volts/amps have not really changed in 2 years.. I still see 13.6v when drawing 15A.
 
edmondthx1138 said:
My problem presents as my Dynon HDX-1100 displaying Lanes A+B at 14.0 to 14.1V, and battery volts at 13.0 (Low, Yellow warning) and Generator Amps is 4. No faults, everything kept running. It apparently happened shortly before landing whilst doing pattern work.

I'm looking at replacing my generator/stator assembly.
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That sounds like Generator A is working good - since the ECU is reporting 14.0v. Generator B is apparently having some issues. Check the Regulator B connector and make sure the pins inside are happy.. no corrosion or burning. Aside from that, it does sound like its a regulator or generator issue. Does your Rotax serial # indicate that some bulletins apply to your engine? such as ASB-912 i-016 Inspection/Replacement of oil spray nozzle or even the older/non-mandatory SI-912 i-028 Change of Oil Cooling of Stator
 
I already spoke with some Rotax experts and the diagnostic I used is simple:

Measure the resistance from each of the six stator output wires (3 black for Reg A, 3 Yellow for Reg B) to EMS ground. A good stator should read open (i.e. not shorted to ground). A reading of 0 ohms means a shorted stator needs replacement.
 
rcarsey said:
That sounds like Generator A is working good - since the ECU is reporting 14.0v. Generator B is apparently having some issues. Check the Regulator B connector and make sure the pins inside are happy.. no corrosion or burning. Aside from that, it does sound like its a regulator or generator issue. Does your Rotax serial # indicate that some bulletins apply to your engine? such as ASB-912 i-016 Inspection/Replacement of oil spray nozzle or even the older/non-mandatory SI-912 i-028 Change of Oil Cooling of Stator
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Did you run across trying to remove the ignition housing? There is a stud protruding to hold the Rotax intake manifold support. It apparently must be removed or the entire intake manifold support must be removed. (btw, I already have the new housing and stator. Gen B is definitely bad)
 
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