fbpx

 

First, an idiot-check on my troubleshooting to identify a bad ignition module:

I have a 914 UL with 966726 ignition modules. It recently got more difficult to start and I noticed an intermittent reduction in RPM that seemed very much like an ignition circuit cutting out. For a while now, by the time I could turn an ignition switch off to troubleshoot, the RPM would come back up. Today, however, it happened right as I was rolling out on landing, so I turned off the module "B" ignition and the engine quit, indicating a bad "A" module. I swapped the 6-pin pickup connectors between the modules, and ran it at low RPM, being very patient waiting for the fault. I was able to kill the "A" switch (now connected to the "B" ignition module) when I saw an RPM decrease, and the engine died. I believe this confirms that module "A" is bad. It may also be that a charging coil is bad, but that seems less likely. If that doesn't seem right, please let me know.

Next, can I direct-replace a 966726 with a 965444? It appears I can, but the soft start won't work unless I also wire that. Since I only need to replace 1 module, I do not plan to wire the soft start for now. I do have the updated flywheel, and I've never had an issue with starting until the ignition started misbehaving. 

 

Thanks in Advance.

  • Re: Need to Replace Ignition Module 966726.

    by » 5 months ago


    Sounds like you have one of the newer 2 x 6-pin modules, so what you are saying is that you have only swapped the one that consists of:

    1. pick up 1/2

    2. pick up 3/4

    3. generator coil

    4. ignition switch

    Initially switching off the ignition switch connected to B killed the engine, indicating that there could be a fault with:

    1. SMD A

    2. ignition switch A

    3. generator A

    4. HT components connected to A (unlikely that they are all faulty)

    5. ground connection to A

    6. pickup coils A

    After swapping the pickup connector, switching off ignition switch A which was now connected to SMD B killed the engine, eliminating the following as sources of the fault:

    1. pickup coils A

    2. generator A

    3. ignition switch A

    So that leaves you with:

    1. ground connection to A

    2. SMD A

    3. HT components connected to A

    It should be easy to check the 2 ground connections that go to SMD A via the other 6-pin connector. It is unlikely that you have faults in both HT coils/leads/plugs, so that probably leaves you with the SMD module. I think that you have eliminated the charging coil by swapping it.


  • Re: Need to Replace Ignition Module 966726.

    by » 5 months ago


    I did trace the ground lead looking for a damaged wire that could be grounding, and checked that the switch breaks continuity with ground at the pin in the connector. I can't totally rule out that there's an intermittent ground fault when it's running and vibrating, but the cutouts don't "feel" like an intermittent ground in their frequency or duration. 

    I appreciate your insight. It sounds like the next thing to do is pony up for an $MD module. Can anyone confirm that 965444 is an appropriate replacement? The parts manual calls for 965442, which costs $400 more than the 965444. They look identical except 965444 had a pin populated in the connector for duct start. I can't quite tell if I'd have to modify the connector on 965444.

     


  • Re: Need to Replace Ignition Module 966726.

    by » 5 months ago


    hi Brian

    I note you say that you have a type 914.  In your original post you also say you have changed the flywheel?  The type 914 has a special flywheel that gives it staggered run timing, it should not be replaced with the 912 series one.  The ignition A on a 914 is wired to fire all top spark plugs and the B to fire all bottom.  This is not the same as the type 912 engines.  

    The older SMD modules have changed numbers as Rotax replaced out of production electronic components internally in the module.  the newer part number reflects the changes from Rotax.  As you noted the 914 would not have the delay pin connected for soft start. 

    cheers


  • Re: Need to Replace Ignition Module 966726.

    by » 5 months ago


    It is an overhauled 914, and has the most recent version of the 914 Flywheel. I did not replace it with a 912 Flywheel.

    Tge most current part number in the Rotax parts manual for the 914 SMD module is 965442, which is not in stock anywhere and costs $400 more than the 965444 that is called out for the 912. The LEAF parts book shows 965444 as the correct part number for the 914, and various internet sources also say that 965442 and 965444 are interchangable on engines without soft start. So I'm 95% sure I can use a 965444. I'm hoping someone can confirm.


You do not have permissions to reply to this topic.