912 UL Ignition coils

When you talk about both "CDIs" I assume you mean the A and B Electronics Modules. (Mag-A, Mag-B)

These have changed over the years...

Looking at the connections to EACH Module, Do you have ... ???

A 4-pin connector and Six 1-pin connections.  (4+1)

A 6-pin Connector, A 4-Pin Connector, and One 1-pin connection. (6+4+1)

Two 6-pin connectors. (6+6)

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Are you saying that the Bottom Electronics Module (Mag B) Fails a Mag check?

Mag-A OFF... Engine Stops??

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You have likely knocked a connector loose that you haven't noticed or something is miswired.

Refer to the HMM, Section 74-00-00, chapter 3.13 pages. pages 24-34.

Thank you very much for replying to my help message. My 912ul is an older version with the 4 pin connector. CDI's are the top (A) and bottom (B), I already interchange both and are in working condition,: Because the only thing I did was to unplug the ground cables from the igniton coils for cleaning, (At bottom of CDI B), and after several test I found that 2 of the Ignition coils are not working. Looks like if the main key switch is bad, keeping the CDI grounded. 

Do you know how to check the ignition coils, the 4 units underneath of CDI B? I went to the rotax heavy maintenance and found some info but they do not specify where to put the leads of the meter. I'm just an old retired minister from my secular Job but never from the church and not to much hands on with the  multimeter.

Again, thanks for your kindness of trying to help me and your patience for reading my sorrows.

Pastor Luis

If BOTH Ignition coils are not working, it is improbable that you have two Bad Coils, Is it More probable that you have ONE problem somewhere else.

If you suspect that the MAG Switch/Key circuit has a problem, Disconnect the Single Pin Connector with the BROWN wire coming out of the "B" Electronics Module.

Check that you nave Not swapped the BROWN and the BLACK wires accidentally.

The BROWN Wire coming from the MAG Switch should be OPEN in the RUN Position and GROUNDED in the OFF Position.

CAUTION: With this Pin disconnected the Engine will continue to run without regard to the Key position until this connector is reattached or the Fuel Valve is closed and the engine runs out of fuel.  Use Extreme Caution in the vicinity of the Propeller.

Thanks Bill,

I have a feeling that the broblem is on the key switch, I will do monday morning ifw the good Lords permits that test, I will keep you posted.

Pastor Luis

Bill, Right on the money! The key switch someway was shorted. I checked with my meter and always on kill wiere was gounded at all time. This switch  came from a cessna plane, I switch it thinking was the best but anyway is man made.  My Rotax 912 UL is an old one but xtremely good engine, I was doing maintenance on the CDI's, means cleaning connectors and pasting with D-electric paste,  the (A) CDI ( one pin and 4 pin Conn),  In the main cable branch where the 4 pin connector is, one of the small male connector cable just came off due corrosion I assume, but I was able to repaired it back. I know that is not acceptable but for a retired minister with just Social Security income, at the moment not able to buy a new one do high cost. I weld the cable back, insulated where the soldering was done hope with my heart that this work if not I will be grounded.  Still looking for a good used one.

Thanks for your kindly patience and help.

Pastor Luis